Electronic devices and precursor articles

ABSTRACT

A first polymer latex and second polymer latex can be mixed to form a dried primer layer on a substrate to adhere patterned materials having fine lines. The first polymer latex comprises a first polymer and a first surfactant such that a dried coating of the first polymer latex has a surface polarity of at least 50%. The second polymer latex comprises a second polymer and a second surfactant such that a dried coating of the second polymer latex has a surface polarity of less than or equal to 27%. Moreover, a dried coating of the mixture has a surface polarity of at least 15% and up to and including 50%. Primed substrates are useful for preparing electrically-conductive articles having electrically-conductive fine lines directly on a dried primer layer by applying a patterned material to a substrate. Such articles can be used as touch screen displays in various electronic devices.

RELATED APPLICATIONS

Reference is made hereby to the following copending and commonlyassigned patent application and patents, the disclosures of all of whichare incorporated herein by reference:

U.S. Ser. No. 14/174,879 (filed Feb. 7, 2014 by Shukla and Mis), nowissued as U.S. Pat. No. 9,207,533;

U.S. Ser. No. 14/197,293 (filed Mar. 5, 2014 by Shukla and Mis), nowissued as U.S. Pat. No. 9,188,861;

U.S. Ser. No. 14/311,445 (filed on Jun. 23, 2014, by Honan, Schell,Kane, Landry-Coltrain, and Bauer) entitled “Patterned and PrimedTransparent Articles,” now issued as U.S. Pat. No. 9,205,628;

U.S. Ser. No. 14/311,453 (filed on Jun. 23, 2014, by Landry-Coltrain,Bauer, Honan, Schell, and Kane) entitled “Preparation of Patterned orElectrically-Conductive Articles,” now issued as U.S. Pat. No.9,505,942; and

U.S. Ser. No. 14/311,435 (filed on Jun. 23, 2014, by Schell, Kane,Honan, Landry-Coltrain, and Bauer) entitled “Latex Primer Compositionand Latex Primed Substrates.”

FIELD OF THE INVENTION

This invention relates to precursor articles and devices prepared usinga coating composition and substrates having the coating compositioncoated on a support (for example, a transparent support). This coatingcomposition performs as a primer layer to adhere patterned materials tothe substrate, and comprises a mixture of two different polymer latexes,each containing polymer particles and a surfactant. The resultingpatterned articles can be used for various purposes and when thepatterns are electrically-conductive materials, the patterned articlescan be used as electrically-conductive films in, for example, devicescontaining touch screens.

BACKGROUND OF THE INVENTION

Primed substrates are used in many industries in order to better adhereoverlying layers, patterns, or text. The term “primed” generally refersto the use of a coating, usually a dried polymeric coating, which hasgood adhesion both to the underlying substrate of a desired smoothnessand composition and to overlying materials.

For example, patternable materials can be used in various industries toprovide patterns of conductive or non-conductive lines, solid areas,text, grids, electrical circuits, or other shapes. Relief printingmembers can be used to apply these patterns to various substrates, andthe resulting patterns can be further treated to provide electricalconductivity or other properties for use in the electronics, display, orenergy industries. For example, electrically-conductive patterns can bedesigned and prepared on transparent substrates for use in variousdisplay devices for example as touch screens.

Polyester and other polymeric films have been well known for decades asuseful substrates on which coatings or patterns have been applied.Polymeric films (or articles) of this type are often more suitable forvarious purposes including printing members, imaging elements, anddisplay devices because of their strength, flexibility, and potentialtransparency. However, a practical difficulty often arises, dependingupon the materials to be applied, in the course of attempting to produceand maintain strong adhesive forces between the polymeric substrates andoverlying coatings or patterns because the polymeric substrates aregenerally highly hydrophobic and overlying coatings or patterns may beless hydrophobic in nature. Alternatively, the polymeric substrates canless hydrophobic than the overlying coatings or patterns.

Many problems arise from poor adhesion in various industries. Touchsensitive panels or displays require very fine lines (on the order ofless than 20 μm in width) in predetermined patterns to achieve desiredelectrical conductivity simultaneously with high visual transparency (orhigh integrated transmittance).

When adequate adhesion is not achieved or maintained during manufactureand use of fine lines of electrically-conductive materials includingelectrically-conductive metals or metal precursors, desiredelectrical-conductivity or capacitance is not achieved. U.S. PatentApplication Publication 2007/0170403 (Conaghan et al.) describes theseadhesion problems and some proposed solutions by using various adhesiveor primer layers on substrates or the incorporation of adhesionpromoting compounds into applied conductive “inks” (compositions).

For example, adhesion and various surface properties of flexible andtransparent substrates can be improved using polymeric primer layersapplied to supporting surfaces of polymeric films. The desire is tobetter adhere later applied materials especially when those materialsare applied in a uniform fashion. Examples of primer layer compositionsused for this purpose are described for example in U.S. Pat. No.6,162,597 (Bauer et al.) and U.S. Pat. No. 6,165,699 (Bauer et al.).

Moreover, U.S. Patent Application Publication 2013/0319275 (Fohrenkammet al.) describes a means for improving flexographic printed conductivelines by designing the substrate and printed ink to have a uniquepolarity relationship.

The production of touch screen sensors and other transparent conductivearticles in roll-to-roll production methods on flexible and transparentsubstrates using “additive processes” for deposition ofelectrically-conductive patterns that provide the functionality of thesensor has been the subject of recent development in the industry. Ofparticular importance is the ability to produce a touch screen sensorthat has both the desired electrical performance as well as appropriateoptical properties (transmittance) in the visible portion (touch region)of the touch screen sensor. To achieve the necessary conductive andoptical properties, average line widths of electrically-conductive linesin the electrically-conductive grid of less than 10 μm are greatlydesired.

The flexible and transparent substrates used in such processes should beoptically clear (high integrated transmittance) and colorless andexhibit low haze. The application of electrically-conductive patternsusing additive processes such as flexographic printing ofelectrically-conductive materials or seed metal compositions requiresthe flexible and transparent substrate to have appropriate surfaceenergy and roughness consistent with the scale of the fine features (forexample, fine lines) to be applied. Considerable effort is being exertedin the electronics industry to achieve these necessary features.

WO 2013063188 (Petcavich et al.) describes a method for producing amutual capacitance touch sensor comprising a dielectric substrate byprinting, using a flexographic printing process with at least a firstmaster plate and a first ink, a first pattern on a first side of adielectric substrate; and curing the printed dielectric article. Asecond ink can be similarly applied and cured to form a second patternon a second surface of the substrate. Both patterns can then beelectrolessly plated with a conductive material. The resultingdielectric article is described to have a thickness of 1 μm to 1 mm anda preferred surface energy of from 20 Dynes/cm to 90 Dynes/cm.

Continued efforts are being directed to finding a cost effective way toprovide flexible and transparent substrates having the desired surfaceand optical properties for various electronic devices such as touchscreen sensors and other optical displays. These efforts areparticularly directed at making and using such substrates in highefficiency roll-to-roll manufacturing operations in which the substratesare subjected to various chemical and mechanical operations.

In particular, there is a need in the art for flexible and transparentsubstrates that exhibit low haze, low color, and surface uniformity andare thus more suitable for adhering fine features such as thin lines,text, or small shapes, and are particularly suitable for fine lines thatare electrically-conductive. Flexible and transparent substrates arealso desirable that exhibit strong adhesion to “printed” patterns suchas those applied by flexographic printing of metal-containingcompositions that are inherently or can be further treated to becomeelectrically-conductive.

SUMMARY OF THE INVENTION

The present invention addressed various problems encountered in the artwith a device comprising a transparent electrically conductive film thatcomprises:

one or more electrically-conductive metal patterns disposed directly ona transparent polymeric substrate that comprises a transparent polymersupport and a dried primer layer disposed on at least one supportingsurface of the transparent polymer support, the dried primer layercomprising a mixture of:

a first polymer latex comprising a first polymer and a first surfactantsuch that a dried coating of the first polymer latex has a surfacepolarity of at least 50%, and

a second polymer latex comprising a second polymer and a secondsurfactant that is different from the first surfactant such that a driedcoating of the second polymer latex has a surface polarity of less thanor equal to 27%,

wherein the dried primer layer has a surface polarity of at least 15%and up to and including 50%, and

wherein each of the one or more electrically-conductive metal patternscomprises a touch region comprising electrically-conductive lines havingan average line width of less than 15 μm.

Moreover, a method for providing a plurality of precursor articlescomprises:

providing a continuous web of a transparent polymeric substrate thatcomprises a transparent polymer support and a dried primer layerdisposed directly on at least one supporting surface of the transparentpolymer support, the dried primer layer comprising:

a first polymer latex comprising a first polymer and a first surfactantsuch that a dried coating of the first polymer latex has a surfacepolarity of at least 50%, and

a second polymer latex comprising a second polymer and a secondsurfactant that is different from the first surfactant such that a driedcoating of the second polymer has a surface polarity less than or equalto 27%,

wherein the dried primer layer has a surface polarity that is at least15% and up to and including 50%,

forming a first curable pattern on the dried primer layer in a firstportion of the continuous web, the first curable pattern comprising aphotocurable or thermally curable composition comprising metal seedparticles, by direct contact of the dried primer layer in the firstportion of the continuous web with a flexographic printing membercarrying the photocurable or thermally composition,

advancing the continuous web comprising the first portion comprising thefirst curable pattern to be proximate a curing station and curing thefirst curable pattern, thereby forming a first cured pattern on thefirst portion, which first cured pattern comprises the metal seedparticles,

forming a second curable pattern on the dried primer layer in a secondportion of the continuous web, the second curable pattern comprising thesame or different photocurable or thermally curable compositioncomprising the same or different metal seed particles, by direct contactwith a flexographic printing member carrying the same or differentphotocurable or thermally curable composition,

advancing the continuous web comprising the second portion comprisingthe second curable pattern to be proximate a curing station and curingthe second curable pattern, thereby forming a second cured pattern onthe second portion, which second cured pattern comprises the same ordifferent metal seed particles,

optionally, carrying out the forming and advancing features one or moretimes for additional respective portions of the continuous web using thesame or different curable or thermally curable composition and the sameor different flexographic printing member to form additional curedpatterns on the additional respective portions, and

winding up the continuous web comprising first, second, and optionaladditional cured patterns to form a roll of a plurality of precursorarticles.

The various embodiments of the present invention provide a number ofadvantages. Most importantly, the compositions and primed substratesprovided by the invention exhibit desired surface characteristics forapplication and adherence of various compositions in patterns containingfine features, including but not limited to lines having an average linewidth of less than 15 μm or more likely less than 15 μm. For example,such patterns can be provided using a photocurable of thermally curablecomposition containing metal seed particles, and the patterns can besuitable electrolessly plated to provide electrically-conductivepatterns with desired fine features. The substrates and articlescontaining them exhibit low haze, low color, desired surface uniformity(coating appearance), and high integrated transmittance (at least 88%).These advantages are achieved by “priming” a suitable support material(such as a transparent support material) with a primer compositioncomprising a mixture of a first polymer latex and a second polymer latexhaving the properties and compositions described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a flexographic printing system usefulfor roll-to-roll printing (or imaging) on both sides of a substrate ofthis invention, in which a representative photocurable composition(patterned material) and a method of the present invention are used.

FIG. 2 is a high-level system diagram for an apparatus (device)comprising a touch screen with a touch sensor that can be prepared(printed) using the present invention.

FIG. 3 is a side view of the touch sensor of FIG. 2.

FIG. 4 is a top view of a conductive metal pattern that has been formedon a first supporting side of a substrate in the touch sensor of FIG. 3.

FIG. 5 is a top view of a conductive metal pattern that has been printedon a second (opposing) side of the substrate in the touch sensor of FIG.3.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to limit the scope of the present invention, asclaimed below. In addition, one skilled in the art will understand thatthe following disclosure has broader application than is explicitlydescribed.

DEFINITIONS

As used herein to define various components of the primer coatingcompositions, dried primer layers, photocurable and thermally curablecompositions, and other compositional features described herein, unlessotherwise indicated, the singular forms “a”, “an”, and “the” areintended to include one or more of the components (that is, includingplurality referents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the term'sdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered to beapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about”. In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

As used herein, unless otherwise indicated, molecular weights are weightaverage molecular weights that can be determined using known proceduresand equipment if the values are not already known from the literature.

Unless otherwise indicated, the term “photocurable or thermally curablecomposition” refers to chemical compositions that are useful in thepractice of the various methods of the present invention and can beprovided in the articles in the present invention. Such compositionshave requisite chemicals that under certain conditions can be cured,polymerized, or crosslinked.

The terms “curing” and “polymerization” are used herein to mean thecombining, for example by covalent bonding, of a large number of smallermolecules, such as monomers or oligomers, in the presence of suitablecatalysts or initiators to form very large molecules, that is,macromolecules or polymers. Curing or polymerization can form linearmacromolecules or three-dimensional macromolecules that are commonlyreferred to as crosslinked polymers including branched-chain materials,or both linear and crosslinked (or branched-chain) materials can beformed at the same time. One type of polymerization that can be carriedout in the practice of this invention is acid-catalyzed (cationic)polymerization. Free radical polymerization can also be carried out inthe practice of this invention. Alternatively, in some embodiments, bothacid catalyzed polymerization and free radical polymerization can becarried out simultaneously.

The terms “photocurable” and “curable” are used to define a material(such as an epoxy material) that will polymerize when irradiated withsuitable radiation, for example irradiated with radiation such asultraviolet (UV), visible, or infrared radiation in the presence of anappropriate photoinitiator composition.

Average dry thickness of layers described herein can be the average oftwo or more separate measurements taken, for example, using electronmicroscopy or optical microscopy in different locations of a dry layer.Obtaining more than 2 separate measurements can be desirable in certainembodiments.

Similarly, the average dry thickness or width of lines, grid lines, orother pattern features described herein can be the average of two ormore separate measurements taken, for example, using electronmicroscopy.

The term “polymerizable epoxy material” is meant to include any materialor compound having one or more oxirane rings that are capable ofundergoing polymerization. This term encompasses epoxy-containingmonomers, epoxy-containing oligomers, and epoxy-containing crosslinkingagents. The singular form of the term is intended to include the pluralform of the term. Oligomeric and multifunctional epoxy materials arealso useful polymerizable epoxy materials.

The term “electron donor photosensitizer” is meant to refer to a lightabsorbing compound used to induce photocuring. Upon photoexcitation, theelectron donor photosensitizer leads to one-electron reduction of theonium salt.

The term “photoinitiator” is meant to refer to any chemical compoundthat decomposes into free radicals or chemical fragments when exposed tolight, to initiate further reaction. In some embodiments, thephotoinitiator is an “onium salt” or an “onium compound” or otherphotoacid generator that is capable of accepting an electron from anexcited electron donor photosensitizer, a process that leads tofragmentation of an onium salt to provide a Brönsted acid that initiatespolymerization of the epoxy material. In other embodiments, thephotoinitiator decomposes into free radicals that proceed to causecuring, polymerization, or crosslinking of vinyl groups.

“Actinic radiation” is used to refer to any electromagnetic radiationthat is capable of producing photochemical or photopolymerization actionin accordance with the present invention and that has a wavelength of atleast 150 nm and up to and including 750 nm, or even at least 190 nm andup to and including 700 nm. The term “exposing radiation” also refers tosuch actinic radiation.

The term “visible light” is used herein to refer to electromagneticradiation having a wavelength (for example, λ_(max)) of greater than 400nm to and up to and including 750 nanometers (nm).

The term “UV light” is used herein to refer to electromagnetic radiationhaving a wavelength (for example, λ_(max)) of at least 150 nm and up toand including 400 nm.

The terms “near infrared” and “infrared” are used herein to refer toelectromagnetic radiation having a wavelength (for example, λ_(max)) ofat least 750 nm and higher, and typically of at least 750 nm and up toand including 1400 nm.

The term “integrated transmittance” is a parameter used to measure“transparency”. Thus, when supports, substrates, and articles arereferred to as transparent, the integrated transmittance over thevisible region of the electromagnetic spectrum (for example from 400 nmto 750 nm) is 80% or more, or more likely at least 88% or even 93% ormore, as measured for example using a spectrophotometer and knowntechniques. In general, the touch regions in the electrically-conductivearticles or films will have this high integrated transmittance. However,the electrode connector regions or BUS regions are generally much lesstransparent and can generally have an integrated transmittance of lessthan 68%, or less than 50%, or even less than 40% using the sameequipment and procedures noted above.

Alternatively, the integrated transmittance can be associated with thecalculated percentage of the transparent article, support, or substratearea that is not covered by an electrically-conductive pattern in thetouch region.

The term “average line width” in reference to various patterns orpatterned materials described herein, refers to a dimension that isdetermined from two or more separate measurements of the lines indifferent locations of the same or different lines using appropriatemeasurement techniques and equipment that would be known to one skilledin the art. More than 2 of such measurements can be desirable in certainembodiments.

The “touch region” on an electrically-conductive surface, portion, film,or other structure refers to the region of an article having patternedmaterials such electrically-conductive patterns are designed fortouching to manipulate images, “apps” or other digital information in adisplay device. Thus, the touch region is different thanelectrically-conductive electrode connector regions,” “BUS lines,” and“BUS regions.

Surface polarity is defined as described below in the Examples.

Uses

The coating compositions, substrates, articles, and methods describedherein can be used for a variety of purposes where substrates having thenoted properties are needed for further application of materials orforming patterns. For example, the (primer) coating compositions,substrates, and articles described herein are particularly useful forproviding electrically-conductive metal patterns having fine features,for example using electroless plating procedures, that can beincorporated into various devices including but not limited to touchscreen or other display devices that can be used in numerous industrialand commercial products.

For example, touch screen technology can comprise different touch sensorconfigurations including capacitive and resistive touch sensors.Resistive touch sensors comprise several layers that face each otherwith a gap between adjacent layers that may be preserved by spacersformed during manufacturing. A resistive touch screen panel can compriseseveral layers including two thin, metallic, electrically conductivelayers separated by a gap that can be created by spacers. When an objectsuch as a stylus, palm, or fingertip presses down on a point on thepanel's outer surface, the two metallic layers come into contact and aconnection is formed that causes a change in the electrical current.This touch event is sent to a controller for further processing.

Capacitive touch sensors can be used in electronic devices withtouch-sensitive features. These electronic devices can include but arenot limited to, televisions, monitors, and projectors that can beadapted to display images including text, graphics, video images,movies, still images, and presentations. The image devices that can beused for these display devices that can include cathode ray tubes(CRTs), projectors, flat panel liquid crystal displays (LCD's), LEDsystems, OLED systems, plasma systems, electroluminescent displays(ELD's), and field emission displays (FED's). For example, the presentinvention can be used to prepare capacitive touch sensors that can beincorporated into electronic devices with touch-sensitive features toprovide computing devices, computer displays, portable media playersincluding e-readers, mobile telephones and other communicating ordigital storage devices.

Systems and methods of fabricating flexible and optically complianttouch sensors in a high-volume roll-to-roll manufacturing process wheremicro electrically-conductive features can be created in a single passare possible using the present invention. Photocurable or thermallycurable compositions can be used with relief printing members such asflexographic printing plates to form multiple high resolutionelectrically-conductive images from predetermined pattern designs.Multiple patterns can be printed on one or both supportive sides of theinventive substrate as described in more detail below. For example, onepredetermined pattern can be printed on one supporting side of thesubstrate and a different predetermined pattern can be printed on theopposing supporting side of the substrate. The printed patterns of thephotocurable or thermally curable compositions can then be furthertreated to provide electrically-conductive metal patterns containingfine features, such as for example using electroless metal platingtechniques.

Polymer Latexes

A unique composition is provided for the present invention, whichcomposition can be deposited onto a surface using any suitable means isused to provide the advantages of the present invention. Such acomposition can also be generally known as a “coating composition”,“primer layer composition”, or a “primer composition”. This coatingcomposition comprises a mixture of at least a first polymer latex and atleast one second polymer latex. By using the modifiers “first” and“second, it is not intended to infer that one polymer latex (or polymer)is better than the other polymer latex (or polymer) in any givenproperty, but the modifiers are used merely to distinguish two differentpolymer latex compositions. Additional polymer latexes can be present inthe mixture if desired as long as the desired properties (describedherein) are obtained.

First and Second Polymers:

The first and second polymer latexes comprise a first polymer and asecond polymer, respectively. When in the latex form or polymericdispersion, the first and second polymers are generally present in theform of particles that have been formed in micelles using known emulsionpolymerization techniques. While each of the first and second polymerscan be isolated, they are used in the present invention in mixtures ofthe first and second latexes and thus, isolation would likely make itharder to use them in coatings.

At least one of the first and second polymers described herein comprisesa vinyl polymer comprising recurring units derived at least in part fromglycidyl (meth)acrylate (meaning glycidyl acrylate, glycidylmethacrylate, or both), and in most embodiments, each of the first andsecond polymers is derived at least in part from glycidyl(meth)acrylate. In addition, at least one of the first polymer andsecond polymer is crosslinkable, and can be crosslinked for exampleafter coating onto a suitable support such as during drying or variousheat treatments of the substrate. A skilled worker in the art would knowhow to provide crosslinking capability in a given polymer by judiciouschoice in the design of the polymer recurring units and reactive groups.

The first polymer latex used in the present invention comprises one ofmore first polymers and one or more first surfactants (described below)such that a dried coating of the first polymer latex has a surfacepolarity of at least 50% (50% or more) or even at least 55% (55% ormore). In most embodiments, the first polymer latex consists essentiallyof two essential components: one or more first polymers and one or morefirst surfactants.

Particularly useful first polymers are vinyl polymers derived at leastin part from one or more glycidyl-functional ethylenically unsaturatedpolymerizable monomers, such as glycidyl acrylate and glycidylmethacrylate. Thus, the first polymer can be a homopolymer derived fromglycidyl (meth)acrylate, but more likely it is a copolymer derived fromglycidyl (meth)acrylate and one or more other ethylenically unsaturatedpolymerizable monomers. The term “glycidyl” refers to a group comprisingan oxirane ring attached to an alkyl group having 1 to 4 carbon atoms(linear or branched alkyl groups that can also be further substituted),such as methyl, ethyl, isopropyl, and t-butyl groups.

For example, the first polymer can comprise recurring units derived fromglycidyl (meth)acrylate in an amount of at least 75 weight % and up toand including 100 weight %, or at least 75 weight % and up to andincluding 90 weight %, based on the total weight of the first polymer.Particularly desirable first polymers are thus derived from glycidyl(meth)acrylate and one or more other ethylenically unsaturatedpolymerizable monomers (co-monomers) that will substantiallycopolymerize with the glycidyl (meth)acrylate monomers rather thanreacting with the glycidyl groups during emulsion polymerization andthat will facilitate emulsion polymerization of all ethylenicallyunsaturated polymerizable monomers within the reaction dispersion.Suitable vinyl co-monomers include but are not limited to, alkylacrylates and alkyl methacrylates wherein the ester alkyl group has 1 to4 four carbon atoms; other substituted alkyl acrylates and methacrylate;acrylamide and methacrylamides; vinyl halides such as vinyl chloride;vinylidene halides such as vinylidene chloride; vinyl pyrrolidone; otherN-vinyl amides; vinyl pyridines; styrene and styrene derivatives such asα-methyl styrene; butadiene; isoprene; acrylonitrile; methacrylonitrile;and others that would be readily apparent to one skilled in the art.Mixtures of co-monomers can be used if desired. One skilled in the artwould be able to use routine experimentation to determine theappropriate amounts of various co-monomers that would provide thedesired film-forming properties and surface polarity values describedherein.

The first polymer is particularly designed by co-polymerizing one ormore glycidyl (meth)acrylates with one or more alkyl (meth)acrylateswherein the ester alkyl group has at least 2 carbon atoms including butnot limited to, ethyl acrylate, ethyl methacrylate, n-butyl acrylate,n-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate,lauryl acrylate, lauryl methacrylate, allyl methacrylate, hydroxyethylmethacrylate, hydroxyethyl acrylate, and others that would be readilyapparent to one skilled in the art. Particularly useful co-monomers arethe alkyl (meth)acrylates wherein the ester alkyl group has at least 4carbon atoms, including but not limited to n-butyl acrylate, n-butylmethacrylate, n-hexyl acrylate, n-hexyl methacrylate, and cyclohexylmethacrylate.

The second polymer latex useful in this invention comprises one of moresecond polymers and one or more second surfactants (described below)such that a dried coating of the second polymer latex has a surfacepolarity of less than or equal to 28% or less than or equal to 27%. Inmost embodiments, the second polymer latex consists essentially of twoessential components: one or more second polymers and one or more secondsurfactants.

Particularly useful second polymers are vinyl polymers derived at leastin part from one or more glycidyl-functional ethylenically unsaturatedpolymerizable monomers, such as glycidyl (meth)acrylate, for exampleglycidyl acrylate and glycidyl methacrylate, as described above for thefirst polymer. Thus, the second polymer can be a homopolymer derivedfrom glycidyl (meth)acrylate, or a copolymer derived from glycidyl(meth)acrylate and one or more other ethylenically unsaturatedpolymerizable monomers. The term “glycidyl” is defined above.

Thus, the second polymer can comprise recurring units derived fromglycidyl (meth)acrylate in an amount of at least 75 weight % and up toand including 100 weight %, or at least 75 weight % and up to andincluding 90 weight %, based on the total weight of the second polymer.Particularly desirable second polymers are thus derived from glycidyl(meth)acrylate and one or more other ethylenically unsaturatedpolymerizable monomers (co-monomers) that will substantiallycopolymerize with the glycidyl (meth)acrylate monomers rather thanreacting with the glycidyl groups during emulsion polymerization andthat will facilitate emulsion polymerization of all ethylenicallyunsaturated polymerizable monomers within the reaction dispersion.Suitable vinyl co-monomers include but are not limited to, alkylacrylates and alkyl methacrylates wherein the ester alkyl group has 1 to4 four carbon atoms; other substituted alkyl acrylates and methacrylate;acrylamide and methacrylamides; vinyl halides such as vinyl chloride;vinylidene halides such as vinylidene chloride; vinyl pyrrolidone; otherN-vinyl amides; vinyl pyridines; styrene and styrene derivatives such asα-methyl styrene; butadiene; isoprene; acrylonitrile; methacrylonitrile;and others that would be readily apparent to one skilled in the art.Mixtures of co-monomers can be used if desired. As with the firstpolymer, one skilled in the art would be able to use routineexperimentation to determine the appropriate amounts of variousco-monomers that would provide the desired film-forming properties andsurface polarity values described herein for the second polymer latex.

The second polymer is particularly designed by co-polymerizing one ormore glycidyl (meth)acrylates with one or more co-monomers such as oneor more alkyl (meth)acrylates wherein the ester alkyl group has at least2 carbon atoms including but not limited to, ethyl acrylate, ethylmethacrylate, n-butyl acrylate, n-butyl methacrylate, cyclohexylacrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl methacrylate,allyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate,and others that would be readily apparent to one skilled in the art.Particularly useful co-monomers are the alkyl (meth)acrylates whereinthe ester alkyl group has at least 4 carbon atoms such as n-butylacrylate, n-butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate,and cyclohexyl methacrylate.

As noted particularly in the Invention Examples described below, whilethe first and second polymers can be different materials, it can beuseful for the first and second polymers to have the same composition(same glycidyl-functional recurring units and recurring units fromco-monomers) or have similar or same molecular weight.

Though the molecular weight of the first and second polymers cannotalways be exactly determined because such polymers may have a bridgingstructure obtained from the glycidyl groups, in general each polymerindependently has a molecular weight of at least 10,000 or more likelyat least 50,000.

In addition, each of the first and second polymers can independentlyhave a glass transition temperature (T_(g)) of at least 25° C. or moretypically at least 40° C., and up to and including 75° C. as determinedby Differential Scanning Calorimetry (DSC).

The amount of the first polymer in the first polymer latex and theamount of the second polymer in the second polymer latex can be the sameor different. In most embodiments, the amount of first polymer in thefirst polymer latex is at least 10 weight % and up to and including 40weight %, based on total first polymer latex solids; and the amount ofsecond polymer in the second polymer latex is at least 20 weight % andup to and including 30 weight %, based on total second polymer latexsolids.

First and Second Surfactants:

The first polymer latex comprises one or more first surfactants, each ofwhich is an alkyl sulfonate sodium salt wherein the alkyl group has atleast 10 carbon atoms. For example, the first surfactant can be a sodiumα-olefin (C₁₄-C₁₆) sulfonate, or the first surfactant can be a compoundrepresented by R—CH₂—CH═CH—CH₂—S(═O)₂O⁻Na⁺ wherein R is a C₁₀, C₁₁, orC₁₂ hydrocarbon group, or mixtures of such compounds with different Rgroups that are any of C₁₀ to C₁₂ hydrocarbons groups. One usefulcommercial product containing a first surfactant is Rhodacal® A246L(available for example from Rhodia). Mixtures of such first surfactantscan be used if desired.

The total amount of the one or more first surfactants in the firstpolymer latex is adjusted so that when a mixture of the first polymerlatex and the second polymer latex (described below) is applied to asubstrate and dried (as a primer layer), the total amount of the one ormore first surfactants in that dried primer layer, is at least 1 weight% and up to and including 3 weight %, or typically at least 1.6 weight %and up to and including 2.8 weight %, based on total dried primer layerweight. One skilled in the art would known how much first surfactant toincorporate into the emulsion used to prepare the first polymer latex sothat the requisite amount is present in the dried primer layer in viewof the mixing weight ratio of first polymer latex and second polymerlatex.

The second polymer latex comprises one or more second surfactants, eachof which is an alkyl phenol sulfate ammonium salt having at least 3ethylene oxide units. For example, the second surfactant can be anammonium salt of a sulfate polyethoxy nonylphenol, or the secondsurfactant can be represented by R′-phenyl-(O—CH₂CH₂)_(n)—S(═O)O₂ ⁻NH₄ ⁺wherein R′ is a C₈ to C₁₂ hydrocarbon group and n is at least 3 and upto and including 10, or more likely n is at least 3 and up to andincluding 6. One useful commercial product containing a secondsurfactant is Rhodapex® CO-436 (available for example from Rhodia).Mixtures of such second surfactants can be used if desired.

The total amount of the one or more second surfactants in the secondpolymer latex is adjusted so that when a mixture of the first polymerlatex and the second polymer latex (described below) is applied to asubstrate and dried (as a primer layer), the total amount of the one ormore second surfactants in that dried primer layer, is at least 0.35weight % and up to and including 1.1 weight %, or typically at least0.45 weight % and up to and including 0.9 weight %, based on total driedprimer layer weight. One skilled in the art would known how much secondsurfactant to incorporate into the emulsion to prepare the secondpolymer latex so that the requisite amount is present in the driedprimer layer in view of the mixing weight ratio of first polymer latexand second polymer latex.

The first polymer and the second polymer are generally dispersed asfinely divided particles in individual aqueous dispersions that comprisefirst and second polymer latexes, respectively. When these polymerlatexes are mixed according to the present invention, they can beapplied to a suitable substrate as a coating formulation in any suitablemanner. Some water in each polymer latex can be replaced with awater-miscible organic solvent (such as methanol or acetone).

It is generally desired to use first and second polymer latexes havingaverage first and second polymer particle sizes, respectively andindependently, of less than 200 μm, more likely less than 150 μm, andeven more desirably less than 100 μm. In order to achieve small andnarrow polymer particle size distributions, it may be necessary in theemulsion polymerization for either or both of the first polymer latexand the second polymer latex to include first and second surfactantamounts that exceed the amounts described in the preceding paragraphs.However, the total first and second surfactant amounts can be reducedbelow the highest limit described for the present invention by the useof dialysis to remove excess first and second surfactants.

Each of the first polymer latex and the second polymer latex can beprepared using emulsion polymerization or obtained as an aqueousdispersion of particulate emulsion polymerizate. The emulsionpolymerization procedure including useful conditions and reactants areknown in the art and representative details are provided in U.S. Pat.No. 6,162,597 (Columns 5-7) the disclosure of which is incorporatedherein by reference. The first and second surfactants described aboveare included in the preparation of the first polymer latex and secondpolymer latex, respectively, for example as at least one of the anionicsurface active agents. However, the preparation of the first and secondpolymer latexes is not limited to using only the first and secondsurfactants, respectively. Representative preparatory methods areprovided below with the Examples.

Coating Compositions

Each of the first polymer latex and second polymer latex canindependently comprise one or more water-miscible organic solvents in anamount of up to and including 10 weight %, based on the total latexweight; one or more surface active agents; one or more inorganic mattingagents (as long as haze is not significantly increased and transparencyis not significantly diminished); antistatic agents; acids or bases toadjust pH; and buffers.

It can also be desirable to incorporate one or more crosslinking agents(can also be known in the art as “hardeners”) in known amounts tofurther facilitate crosslinking of the polymer latex particles once theyare applied to a support and dried. Useful crosslinking agents includebut are not limited to, aldehyde-containing compounds such asformaldehyde and glyoxal, ethyleneimine-containing compounds such astetramethylene-1,4-bis(ethyleneurea), esters of methane sulfonic acidsuch as trimethylenebis methanesulfonic acid ester, active vinylcompounds such as bisacroyl urea and methylenedivinylsulfonic acid,glycidyl-containing compounds such as bisphenolglycidyl ether, andisocyanates.

However, it is optimal that neither first polymer latex nor secondpolymer latex contains significant amounts of coalescing aides such asresorcinol and other compounds described for this purpose in Col. 6,line 53 to Col. 7, line 3 of U.S. Pat. No. 6,162,597 (noted above). Itis particularly desired that both first and second polymer latexescomprise less than 1 weight % of such coalescing aides such asresorcinol, based on the total weight of the dried primer layer(described below) when the two polymer latexes are mixture and appliedto a support.

Thus, in some embodiments of the composition described herein, a driedprimer coating of the composition has a surface polarity of at least 28%and up to and including 50%. In addition, such compositions can have thefollowing properties:

the first polymer comprises at least 75 weight % and up to and including90 weight % of recurring units derived from glycidyl (meth)acrylate andat least 10 weight % and up to and including 25 weight % of recurringunits derived from n-butyl (meth)acrylate, based on the total firstpolymer weight, which first polymer has a glass transition temperatureof at least 50° C. and up to and including 70° C., and the firstsurfactant is a sodium α-olefin (C₁₄-C₁₆) sulfonate;

the second polymer comprises at least 75 weight % and up to andincluding 90 weight % of recurring units derived from glycidyl(meth)acrylate and at least 10 weight % and up to and including 25weight % of recurring units derived from n-butyl (meth)acrylate, basedon the total second polymer weight, which second polymer has a glasstransition temperature of at least 50° C. and up to and including 70°C., and the second surfactant is an ammonium salt of a sulfatedpolyethoxy nonylphenol;

a dried coating of the composition has a surface polarity of at least28% and up to and including 50%;

the weight ratio of the first polymer latex to the second polymer latexin the mixture is from 1:1 and to and including 2.5:1;

the first surfactant is present in a dried coating of the mixture in anamount of at least 1 weight % and up to and including 3 weight %, basedon total dry coating weight;

the second surfactant is present in a dried coating of the mixture in anamount of at least 0.35 weight % and up to and including 1.1 weight %,based on the total dry coating weight; and

the total amount of the first and second surfactants in a dry coating ofthe mixture is less than 3.35 weight %, based on the total dry coatingweight.

Substrates

The composition (“primer” composition) described above can be applied ina suitable manner to any suitable support for further processing ortreatment for a given industrial purpose to form a substrate of thisinvention. The resulting substrates can be opaque, transparent, ortranslucent, or a combination thereof having portions that are opaqueand portions that are transparent.

For example, the dried primer layer can be formed on any suitablesupport material as long as it does not inhibit the purpose for whichthe resulting article is designed. For example, supports can be formedfrom materials including but not limited to, polymeric films, metals,glasses (untreated or treated for example with tetrafluorocarbon plasma,hydrophobic fluorine, or a siloxane water-repellant material), siliconor ceramic wafers, fabrics, papers, and combinations thereof (such aslaminates of various films, or laminates of papers and films). Theresulting substrate can be rigid or flexible. Particularly usefulsupport materials are polyesters, polycarbonates, polystyrenes,polyimides, polyamides, and composites thereof.

The support used in the substrate can have any desired dry averagethickness that is generally at least 50 μm and up to and including 3,000μm. Most continuous webs that are used in the present invention wouldhave an average dry thickness (dried primer layer and support) dependingupon the eventual use of the article formed therefrom, for example itsincorporation into various articles or optical or display devices. Forexample, the substrate dry thickness (including dried primer layer,support, and any optional layers or coatings) can be at least 50 μm andup to and including 250 μm, and especially for polymeric films, thesubstrate dry thickness can be at least 80 μm and up to and including175 μm or at least 100 μm and up to and including 125 μm.

The substrate of the present invention can be provided in various forms,such as for example, individual sheets in any size or shape, andcontinuous webs such as continuous webs of transparent substratesincluding transparent polyester supports that are suitable forroll-to-roll operations. Such continuous webs can be divided or formedinto individual first, second, and additional portions that can be usedto form the same or different patterns of patterned material (describedbelow).

Before or after a dried primer layer is formed on one or both supportingsides of a support, the support material (especially if a polymericmaterial) can be treated in a suitable manner to improve adhesion of thedried primer composition, to reduce shrinkage of the substrate duringmanufacture, coating, or further operations described below. Forexample, it is generally desired that polyester or other polymericsupports are stretched in one or both planar directions (machine andtransverse directions) either prior to or after formation of the driedprimer layer. However, in most embodiments, transverse and machinedirection stretching is carried out using known procedures andconditions after a dried primer layer is formed on one or bothsupporting sides of the support. Heat treatment (or heat relaxation)after these stretching procedures at a temperature of for examplegreater than 100° C. and up to and including 150° C. for severalminutes, can provide thermal energy sufficient to coalesce first andsecond polymer particles in the dried primer layer to form a relativelyuniform dried primer layer film and to crosslink one or both of thefirst and second polymers if they have requisite crosslinkable groups.

Other useful support treatments include corona discharge treatment,flame treatment, and various cleaning and washing procedures.

The primer composition described above is generally applied to asuitable support described herein (such as a polyester support includinga continuous polyester web) at a sufficient coverage to provide thedesired dry thickness of the dried primer layer described herein, forexample at a coverage of at least 30 mg solids/m² and up to andincluding 300 mg solids/m² using any of the techniques described herein.The coating process can occur at any time during manufacture of thesubstrate of this invention such as before biaxial stretching asdescribed above, or after machine direction stretching and beforetransverse stretching, or after biaxial stretching.

It would also be apparent to one skilled in the art that the desired drythickness of a given dried primer layer can be achieved by multiplecoatings of the same or different primer compositions according to thepresent invention so that the final dried primer layer can be acomposite of multiple sub-layers having the same or different chemicalcomposition and dry thickness. If such a composite of multiple layers isformed, the surface polarity of the final dry primer layer would be, bydefinition, an evaluation of the outermost surface of the compositedried primer layer.

As noted above, particularly useful substrates comprise a support(comprised of one or more materials described in the precedingparagraph) on which can be directly disposed a dried primer layer thatis composed of the composition described herein. The dried primer layercomprises a mixture (for example, coalesced mixture) of a first polymerlatex and a second polymer latex as defined above. In addition, thedried primer layer has a surface polarity of at least 15% and up to andincluding 50%, or of at least 22% and up to and including 45%. It isparticularly desirable that the support is compose of one or moretransparent polymeric materials such as a polyester, a mixture ofpolyesters, or a mixture of a polyester and another polymer, and theresulting substrate can have an integrated transmittance of at least 88%and more likely at least 93%. For example, particularly usefultransparent support materials can be composed of poly(ethyleneterephthalate) and poly(ethylene naphthalate).

While in most embodiments the dried primer layer is disposed directly onthe support (meaning that there are no intermediate layers purposelyformed or provided between the dried primer layer and the support), itis also possible that the support can be coated with one or moredifferent primer polymers or mixtures of polymers to form one or more“intermediate primer layers” using materials that are generally knownfor this purpose in the photographic art, and the dried primer layeraccording to this invention can then be applied directly to the one ormore intermediate primer layers. Such intermediate primer layers can beformed on one or both supporting sides of the support, and then thedried primer layer according to the present invention can be directlyformed on the intermediate primer layer on one or both supporting sidesof the support.

The dried primer layer can be thusly disposed on at least one supportiveside of the support, and in many embodiments, the same or different (incomposition, thickness, or surface polarity) dried primer layer can bedisposed directly on both supporting sides of the support (that is, afirst supporting side and a second opposing supporting side). By“supporting side”, it is meant to refer to a planar side of the supportrather than an edge of the support material. For example, the driedprimer composition according to the present invention can be disposed onone supporting side of the support while other (non-inventive) polymer(or primer) layers can be disposed on the opposing supporting side ofthe support.

A dried primer layer can be formed on at least one supporting side of asupport by application of the mixture (composition) of latexes describedabove using any suitable manner such as dip coating, roll coating,hopper coating, spray coating, spin coating, or any other method thatprovides a generally uniform coating that can be dried in any suitablemanner (such as using procedures and equipment known in the photographicsupport art). Alternatively, a pattern of the primer composition can beapplied to the support (or to any intermediate primer layers thereon),for example, using ink jetting, photolithographic imprinting,“flexographic” printing using relief printing members such asflexographic printing members (for example, flexographic printing platesand flexographic printing sleeves), lithographic printing usinglithographic printing plates, and gravure or intaglio printing usingappropriate printing members.

The dried primer layer disposed on the support can have severaldesirable properties. For example, the weight ratio of the dried firstpolymer latex to the dried second polymer latex in the dried primerlayer is from 1:3 and to and including 3:1 or from 1:1 and to andincluding 2.5:1.

Moreover, the first surfactant (described above) can be present in thedried primer layer in an amount of at least 1 weight % and up to andincluding 3 weight %, and more typically of at least 1.6 weight % and upto and including 2.8 weight %, based on the total dried primer layerweight.

In addition, the second surfactant is present in the dried primer layerin an amount of at least 0.35 weight % and up to and including 1.1weight %, or typically of at least 0.45 weight % and up to and including0.9 weight %, based on the total dried primer layer weight.

The total amount of the first and second surfactants in the dried primerlayer is at least 1.35 weight % and up to and including 3.35 weight %,based on the total dried primer layer weight.

It is also useful that the dried primer layer (or composite ofsub-layers as described above) has an average dry thickness of at least0.05 μm and up to and including 0.4 μm, or typically of at least 0.05 mand up to and including 0.2 μm, or even of at least 0.07 μm and up toand including 0.2 μm. A skilled worker would know how to determine thedensity of a particular primer composition prepared according to thepresent invention and then to calculate the wet coverage to be appliedto achieve the desired dry thickness of the resulting dried primerlayer.

Upon application of a coating comprising a mixture of the first andsecond polymer latexes as described above to a suitable support, anddrying, the mixture of latex particles typically “coalesce” to form apolymer film that generally has uniform composition over the entiresupporting surface to which it is applied. In many embodiments, thelatex particles can also crosslink among themselves to provide a moredurable surface that is more resistant to degradation by organicsolvents. Such durable uniform dried primer layer coatings can thenprovide more suitable surfaces for the application of curablecompositions.

Articles

The substrates described above can be used to provide articles in whicha patterned material is disposed directly on the dried primer layer thatis in turn disposed directly (in most embodiments) on the support (suchas a transparent polymeric support). It is particularly useful that evenwith the patterned material being present, the article can have anintegrated transmittance of at least 88% or typically of at least 95%.Such articles can comprise a dried primer layer having the propertiesdescribed above for the substrates, including the average dry thickness,weight ratio of the first polymer latex to the second polymer latex, theparticular compositions and glass transition temperatures of the firstand second vinyl polymers in the latexes, and the particular first andsecond surfactants (and their amounts).

It is also desirable that such dried primer layers in the articles aresubstantially free of resorcinol, for example less than 1 weight % ofresorcinol, or even less than 0.5 weight % based on the total driedprimer layer weight.

The patterned materials can be provided in a patternwise fashion in thearticles of this invention in any suitable manner, for example using themeans and techniques described above for forming the dried primer layersincluding but not limited to, using flexographic printing members suchas flexographic printing plates, flexographic printing cylinders, andflexographic printing sleeves, using intaglio printing, and usinggravure printing. A patterned material can also be applied to asubstrate using ink jet printing methods and equipment. Once applied, atleast a portion of the patterned material can comprise fine lines havingan average line width of less than 15 μm or even less than 10 μm. Ofcourse, the patterned material need not be entirely composed of suchfine lines, as it can also comprise large areas, text, and variousshapes if desired. But, in most embodiments, at least a portion of thepatterned material comprises predominantly the fine lines so as to forma grid or pattern of the fine lines. In some embodiments, the entirepatterned material on the dried primer layer is composed of such finelines.

Useful patterned materials generally comprise any suitable compositionor “ink” that can be applied to the substrate in a patternwise fashionand that can be used in this form for a particular purpose.

In some embodiments, the term “patterned material” is an“electrically-conductive print material” that is electrically-conductiveor that can be further treated to become electrically-conductive. Suchmaterials can be organic, inorganic, or comprise both organic andinorganic components. Useful electrically-conductive print materialsgenerally exhibit a predetermined activity in response to at least anelectrical potential even though such materials can also be responsiveto other stimuli. Examples of electrically-conductive print materialsinclude but are not limited to, electrically-conductive organic orinorganic polymers (or composites thereof), particles of indium-tinoxide, particles, flakes, or filaments of metals (such as gold, silver,copper, platinum, nickel, iron, aluminum, and palladium), particles ofmetal complexes, metal alloys, and metal precursors, and combinationsthereof. An electrically conductive print material can alternatively bean electrically conductive material precursor such as a metal salt (forexample a silver salt like a silver halide or an organic silver salt),or an electroless metallization catalyst such as palladium particles.Particularly useful electrically conductive print materials includesilver and silver salts, gold, copper, palladium, platinum, nickel,iron, indium-tin oxide, carbon blacks, and combinations thereof.

Moreover, useful electrically-conductive print materials can be of anyform or composition including particulate (or any desired shape),polymeric materials, or non-polymeric molecules. For example, usefulparticulate or film-forming polymeric electrically-conductive printmaterials include but not limited to, polythiophenes, polyanilines,polypyrroles, polycarbazoles, polyindoles, polyazepines,polyethylenedioxythiophenes, poly(3-alkylthiophenes), poly(p-phenylenevinylene)'s, poly(p-phenylene)'s, poly(styrene sulfonic acid) (PSS),poly(p-phenylene sulfide), polyacetylene, poly(3,4-ethylenedioxythiophene) (PEDOT), and a mixture of poly(styrene sulfonic acid)and poly(3,4-ethylene dioxythiophene) (PSS:PEDOT).

In some embodiments, the patterned materials or electrically-conductiveprint materials can comprise or be entirely composed of nanoparticles ofelectrically-conductive materials, and thus whose size is measured innanometers (nm), for example, having at least one dimension less than200 nm and in some embodiments, having an average diameter of at least 3nm to and including 100 nm. Nanoparticles can be provided or used in theform of clusters. The shape of the nanoparticles is not limited andincludes nanospheres, nanorods, and nanocups. For example, usefulelectrically-conductive print materials can include nanoparticles ofcarbon such as carbon black, carbon nanotubes, graphene, and equivalentcarbon-containing materials. Metal nanoparticles and dispersions ofgold, silver, palladium, platinum, and copper are also useful inpatterned materials.

More particularly, the printed materials used in this inventioncomprises particles (such as nanoparticles) of electrically-conductivemetals (or precursors thereof) such as particles of any of silver, gold,copper, palladium, platinum, nickel, and iron, or combinations thereof,which metal particles can be dispersed within a photocurable orthermally curable composition as described below. Precursors of suchmetals, such as salts or metal-ligand complexes of each metal, can alsobe used. In addition, indium tin oxide can be incorporated into apatterned material.

In general, the solid materials of the patterned materials areformulated by being dispersed, dissolved, or suspended in a suitablecarrier liquid, thereby forming a liquid composition (“ink”) forapplication to a substrate as described herein, and particularly using aflexographic printing member as described herein. The carrier liquidsused for this purpose can include organic solvent(s) and water as longas they are compatible with and do not react with (are inert) the solidcomponents of the patterned material. For example, the carrier liquidcan be one or more organic solvents capable of dispersing or suspendingthe solid components such as metal particles in solution sufficient tocarry out the method of this invention. In some embodiments as describedbelow, the carrier liquid can be a reactive component of a photocurableor thermally curable composition that is part of the patterned material.

The patternable material formulation should at least be capable ofwetting at least the uppermost relief surface of a flexographic printingmember as this is the desirable method for applying the patternedmaterial to the dried primer layer of the substrate during the method ofthis invention. The carrier liquid can have some volatility, and canalso cause a certain amount of swelling in the flexographic printingmember, depending upon the type of composition from which theflexographic printing member is prepared. Thus, it is advantageous touse a carrier liquid that will not attack or adversely affect thestability and dimensional size of the elastomeric relief surface of theflexographic printing member. The art provides sufficient teachingrelating to suitable carrier liquids for a particular patternedmaterial. Representative useful carrier liquid solvents include but arenot limited to, alcohols (such as isopropyl alcohol, 2-ethyl hexanol,and α-terpenol), acetates (such as ethyl acetate), water, hydrocarbons(such as toluene and cyclohexane), and combinations of misciblesolvents.

In general, before application to a substrate, a patterned materialgenerally has a viscosity of at least 1 cps and up to and including 1500cps, or typically of at least 100 cps and up to and including 1000 cps.Higher viscosity patterned materials can be used if desired. Viscositycan be measured using a conventional means and equipment such as aBrookfield Viscometer DV-II+Pro (Brookfield Engineering Laboratories).

Some useful patterned materials include but are not limited to,electrically-conductive inks containing electrically-conductiveparticles such as metal flakes or particles. Electrically-conductiveinks include electrically-conductive silver-containing inks (such asinks comprising silver nanoparticles), gold-containing inks,copper-containing inks, carbon-containing inks, palladium-containinginks, and other inks containing “seed” materials for electroplating orelectroless plating. Some of such inks can be obtained commercially fromsources such as InkTec (California), Flint Ink Corporation (Michigan),Method Development Company (Chicago), and Novacentrix (Austin, Tex.).Some of these “inks” can be used as a carrier liquid while other inkscomprise both a carrier liquid and one or more electrically-conductivecomponents.

In some embodiments, the patterned materials can further comprise acolorant including but not limited to, dyes, optical absorbers,pigments, opacifiers, and any material that modifies the transmissive orreflective property of the patterned material at any time during themethod of this invention.

As noted above, the patterned materials can be photocurable or thermallycurable. “Photocurable” refers to a composition that can be polymerizedor crosslinked upon exposure to suitable photocuring radiation. Forexample, photocuring can take place upon exposure of the patternedmaterial comprising suitable photocurable components using suitableradiation for example, having a λ_(max) of at least 150 nm and up to andincluding 750 nm, or more likely using radiation having a λ_(max) of atleast 150 nm and up to and including 400 nm. Photoexposure can becarried out using suitable sources of such radiation for a suitable timeto provide the needed curing energy. A skilled worker would know how tooptimize the conditions for achieving desired polymerization orcrosslinking.

Useful thermal curing processes can also be carried out by heating thepatterned material to a temperature of at least 110° C. and up to andincluding 150° C. using a suitable source of heat such a hotplate, oven,infrared heating (for example, exposure to a near-infrared- orinfrared-emitting laser), or other heating apparatus, for a sufficienttime to obtain desired polymerization or crosslinking such as at least10 minutes and up to and including 30 minutes. A skilled artisan canreadily determine the optimal heating temperature and time conditionsthat would be desirable to achieve the desired polymerization orcrosslinking.

More particularly, the patterned material can be a photocurablecomposition comprising metal particles as described above and a freeradical curable composition, an acid catalyzed curable composition, or amixture of both a free radical curable composition and an acid catalyzedcurable composition.

Free radical curable compositions generally comprise one or morematerials that upon exposure to suitable radiation generate freeradicals that in turn cause polymerization or crosslinking of reactivemonomers, oligomers, or polymers are also present. The various requiredand optional components are generally carried within one or moresolvents (carrier solvents) that can be distinct chemical compounds orthey can also be compounds reactive to free radicals (for example, freeradical reactive monomers such as acrylates that also act as carriersolvents). Many such free radical curable compositions are described inthe journal and patent literature.

Similarly, acid catalyzed curable compositions are also known in the artand generally comprise one or more compounds that generate an acidmoiety upon exposure to suitable radiation, which acid moiety thencatalyzes polymerization or crosslinking of suitable chemical compoundsdesigned for such chemical environment.

In still other patterned materials, a photocurable composition caninclude mixtures of chemicals that are both free radical curable andacid catalyzed curable. When both types of curing chemistries are used,the resulting crosslinked matrix can constitute an interpenetratingpolymer network (IPN) including the crosslinked materials. Thisincreased crosslinking density can further increase chemical resistanceand hardness and provide superior properties for the eventualelectrically-conductive metal patterns comprisingelectrically-conductive fine lines.

(a) Photopolymerizable Epoxy Materials

The cationically polymerizable epoxy materials (“epoxies”) are organiccompounds having at least one oxirane ring, which oxirane ring is shownin the following formula:

that is polymerizable by a ring opening mechanism. Such epoxy materials,also called “epoxides”, include monomeric epoxy compounds and epoxidesof the polymeric type and can be aliphatic, cycloaliphatic, aromatic orheterocyclic. These materials generally have, on the average, at leastone polymerizable epoxy group per molecule, or typically at least about1.5 and even at least about 2 polymerizable epoxy groups per molecule.Polymeric epoxy materials include linear polymers having terminal epoxygroups (for example, a diglycidyl ether of a polyoxyalkylene glycol),polymers having skeletal (backbone) oxirane units (for example,polybutadiene polyepoxide), and polymers having pendant epoxy groups(for example, a glycidyl methacrylate polymer or copolymer).

The polymerizable epoxy materials can be single compounds or they can bemixtures of different epoxy materials containing one, two, or more epoxygroups per molecule. The “average” number of epoxy groups per moleculeis determined by dividing the total number of epoxy groups in the epoxymaterial by the total number of epoxy-containing molecules present.

The epoxy materials can vary from low molecular weight monomericmaterials to high molecular weight polymers and they can vary greatly inthe nature of the backbone and substituent (or pendant) groups. Forexample, the backbone can be of any type and substituent groups thereoncan be any group that does not substantially interfere with cationicphotocuring process desired at room temperature. Illustrative ofpermissible substituent groups include but are not limited to, halogens,ester groups, ethers, sulfonate groups, siloxane groups, nitro groups,and phosphate groups. The molecular weight of the epoxy materials can beat least 58 and up to and including 100,000, or even higher.

Useful epoxy materials include those that contain cyclohexene oxidegroups such as epoxycyclohexane carboxylates, such as3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate,3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate. A moredetailed list of useful epoxy materials of this nature is provided inU.S. Pat. No. 3,117,099 (Proops et al.). Still other useful epoxymaterials include glycidyl ether monomers that are glycidyl ethers ofpolyhydric phenols obtained by reacting a polyhydric phenol with anexcess of a chlorohydrin such as epichlorohydrin [for example, thediglycidyl ether of 2,2-bis-(2,3-epoxypropoxyphenol)-propane].

Many commercially available epoxy materials are useful includingglycidyl ethers such as bisphenol-A-diglycidyl ether (DGEBA), glycidylethers of bisphenol S and bisphenol F, butanediol diglycidyl ether,bisphenol-A-extended glycidyl ethers, phenol-formaldehyde glycidylethers (epoxy novolacs) and cresol-formaldehyde glycidyl ethers (epoxycresol novolacs), epoxidized alkenes such as 1,2-epoxyoctane,1,2,13,14-tetradecane diepoxide, 1,2,7,8-octane diepoxide, octadecyleneoxide, epichlorohydrin, styrene oxide, vinyl cyclohexene oxicyclohexeneoxide, glycidol, glycidyl methacrylate, diglycidyl ether of Bisphenol A(for example, those available under the EPON trademark such as Epon™828, Epon™ 825, Epon™ 1004, and Epon™ 1010 from Momentive, DER-331,DER-332, and DER-334 resins from Dow Chemical Co.), vinyl cyclohexenedioxide (for example, ERL-4206 resin from Polyscience),3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (for example,ERL-4221, UVR 6110, or UVR 6105 resin from Dow Chemical Company),3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methyl-cyclohexenecarboxylate (from Pfalz and Bauer),bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate,bis(2,3-epoxy-cyclopentyl) ether, aliphatic epoxy modified withpolypropylene glycol, dipentene dioxide, epoxidized polybutadiene (forexample, Oxiron 2001 resin from FMC Corp.), silicone resin containingepoxy functionality, flame retardant epoxy resins (for example, DER-580resin, a brominated bisphenol type epoxy resin available from DowChemical Co.), 1,4-butanediol diglycidyl ether of phenol formaldehydenovolak (for example, DEN-431 and DEN-438 resins from Dow Chemical Co.),resorcinol diglycidyl ether (for example, CYRACURE™ resin from DowCorning Corp.),2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane,2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-meta-dioxane,vinyl cyclohexene monoxide, 1,2-epoxyhexadecane (for example, CYRACURE™resin from Dow Corning Corp.), alkyl glycidyl ethers such as HELOXY™Modifier 7 and HELOXY™ Modifier 8 (from Momentive), butyl glycidyl ether(for example, HELOXY™ Modifier 61 from Momentive), cresyl glycidyl ether(for example, HELOXY™ Modifier 62 from Momentive), p-tert butylphenylglycidyl ether (for example, HELOXY™ Modifier 65 from Momentive),polyfunctional glycidyl ethers such as diglycidyl ether of1,4-butanediol (for example, HELOXY™ Modifier 67 from Momentive),diglycidyl ether of neopentyl glycol (for example, HELOXY™ Modifier 68from Momentive), diglycidyl ether of cyclohexanedimethanol (for example,HELOXY™ Modifier 107 from Momentive), trimethylol ethane triglycidylether (for example, HELOXY™ Modifier 44 from Momentive), trimethylolpropane triglycidyl ether (for example, HELOXY™ Modifier 48 fromMomentive), polyglycidyl ether of an aliphatic polyol (for example,HELOXY™ Modifier 84 from Momentive), polyglycol diepoxide (for example,HELOXY™ Modifier 32 from Momentive), bisphenol F epoxides (for example,EPN-1138 or GY-281 resin from Huntman Advanced Materials), and9,9-bis>4-(2,3-epoxypropoxy)-phenyl fluorenone (for example, Epon™ 1079resin from Momentive).

Still other useful epoxy materials are resins such as copolymers derivedfrom acrylic acid esters reacted with glycidol such as glycidyl acrylateand glycidyl methacrylate, copolymerized with one or more ethylenicallyunsaturated polymerizable monomers. Other useful epoxy materials areepichlorohydrins such as epichlorohydrin, alkylene oxides such aspropylene oxide and styrene oxide, alkenyl oxides such as butadieneoxide, and glycidyl esters such as ethyl glycidate. Still other usefulepoxy materials are silicones having an epoxy functionality or groupsuch as cyclohexylepoxy groups, especially those epoxy materials havinga silicone backbone. Commercial examples of such epoxy materials includeUV 9300, UV 9315, UV 9400, UV 9425 silicone materials that are availablefrom Momentive.

Polymeric epoxy materials can optionally contain other functionalitiesthat do not substantially interfere with cationic photocuring of thephotopolymerizable composition at room temperature. For example, thephotopolymerizable epoxy materials can also include free-radicallypolymerizable functionality.

The photopolymerizable epoxy material can comprise a blend or mixture oftwo or more different epoxy materials. Examples of such blends includetwo or more molecular weight distributions of photopolymerizable epoxymaterials, such as a blend of one or more low molecular weight (below200) epoxy materials with one or more intermediate molecular weight(from 200 to 10,000) photopolymerizable epoxy materials, or one or moreof such photopolymerizable epoxy materials with one or more highermolecular weight (above about 10,000) epoxy materials.

The photopolymerizable epoxy materials can be used to provide binderfunction if desired for given utilities. Otherwise, non-photocurablepolymers or resins can be included for this purpose if needed.Alternatively, the photocurable acrylates described below can be used toprovide a binder function.

One or more photopolymerizable epoxy materials are included in thephotopolymerizable composition in a suitable amount to provide thedesired efficient photocuring or photopolymerization. For example, theone or more photopolymerizable epoxy materials are present in an amountof at least 10 weight % and up to and including 95 weight %, based onthe total weight of all four (a) through (d) components in thephotocurable composition.

(b) Photoacid Generators

Various compounds can be used to generate a suitable acid to participatein the photocuring of the photopolymerizable composition describedherein. Some of these “photoacid generators” are acidic in nature andothers are nonionic in nature. Other useful photoacid generators besidesthose described below would be readily apparent to one skilled in theart in view of the teaching provided herein. The various compoundsuseful as photoacid generators can be purchased from various commercialsources or prepared using known synthetic methods and startingmaterials.

(i) Onium Salts

Onium salt acid generators include but are not limited to, salts ofdiazonium, phosphonium, iodonium, or sulfonium salts including polyaryldiazonium, phosphonium, iodonium, and sulfonium salts. The iodonium orsulfonium salts include but not limited to, diaryliodonium andtriarylsulfonium salts. Useful counter anions include but are notlimited to complex metal halides, such as tetrafluoroborate,hexafluoroantimonate, trifluoromethanesulfonate, hexafluoroarsenate,hexafluorophosphate, and arenesulfonate. The onium salts can also beoligomeric or polymeric compounds having multiple onium salt moieties aswell as molecules having a single onium salt moiety.

Examples of useful aromatic iodonium salts include but are not limitedto, diphenyliodonium tetrafluoroborate; di(4-methylphenyl)iodoniumtetrafluoroborate; phenyl-4-methylphenyliodonium tetrafluoroborate;di(4-heptylphenyl)iodonium tetrafluoroborate; di(3-nitrophenyl)iodoniumhexafluorophosphate; di(4-chlorophenyl)iodonium hexafluorophosphate;di(naphthyl)iodonium tetrafluoroborate;di(4-trifluoromethylphenyl)iodonium tetrafluoroborate; diphenyliodoniumhexafluorophosphate; di(4-methylphenyl)iodonium hexafluorophosphate;diphenyliodonium hexafluoroarsenate; di(4-pbenoxyphenyl)iodoniumtetrafluoroborate; phenyl-2-thienyliodonium hexafluorophosphate;3,5-dimethylpyrazolyl-4-phenyliodonium hexafluorophosphate;diphenyliodonium hexafluoroantimonate; 2,2′-diphenyliodoniumtetrafluoroborate; di(2,4-dichlorophenyl)iodonium hexafluorophosphate;di(4-bromophenyl)iodonium hexafluorophosphate;di(4-methoxyphenyl)iodonium hexafluorophosphate;di(3-carboxyphenyl)iodonium hexafluorophosphate;di(3-methoxycarbonylphenyl)iodonium hexafluorophosphate;di(3-methoxysulfonylphenyl)iodonium hexafluorophosphate;di(4-acetamidophenyl)iodonium hexafluorophosphate;di(2-benzothienyl)iodonium hexafluorophosphate; and diphenyliodoniumhexafluoroantimonate; and mixtures thereof. Such compounds can beprepared by metathesis of corresponding aromatic iodonium simple salts(such as, for example, diphenyliodonium bisulfate) in accordance withthe teachings of Beringer et al., J. Am. Chem Soc. 81, 342 (1959).

Useful iodonium salts can be simple salts (for example, containing ananion such as chloride, bromide, iodide, or C₄H₅SO₃ ⁻) or a metalcomplex salt (for example, containing SbF₆ ⁻, PF₆ ⁻, BF₄ ⁻,tetrakis(perfluorophenyl)borate, or SbF₅OH₃₁AsF₆ ⁻). Mixtures of any ofthese iodonium salts of the same or different class can be used ifdesired.

Useful sulfonium salts include but are not limited to,triaryl-substituted salts such as mixed triarylsulfoniumhexafluoroantimonates (for example, commercially available as UVI-6974from Dow Chemical Company), mixed triarylsulfonium hexafluorophosphates(for example, commercially available as UVI-6990 from Dow ChemicalCompany), and arylsulfonium hexafluorophosphates (for example,commercially available as SarCa™ KI85 from Sartomer Company).

One or more onium salts (such as an iodonium salt or a sulfonium salt)are generally present in the photopolymerizable composition in an amountof at least 0.05 weight % and up to and including 10 weight %, ortypically at least 0.1 weight % and up to and including 10 weight %,based on the total weight of the all four (a) through (d) components.

(ii) Nonionic Photoacid Generators

Besides onium salts described above, nonionic photoacid generators arealso useful. Such compounds include but are not limited to, diazomethanederivatives such as, for example, bis(benzenesulfonyl)-diazomethane,bis(p-toluenesulfonyl)diazomethane, bis(xylenesulfonyl)-diazomethane,bis(cyclohexylsulfonyl)-diazomethane, bis(cyclopentylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,bis(iso-butylsulfonyl)-diazomethane, bis(sec-butylsulfonyl)diazomethane,bis(n-propylsulfonyl) diazomethane,bis(iso-propylsulfonyl)-diazomethane, bis(tert-butylsulfonyl)diazomethane, bis(n-amylsulfonyl)diazomethane,bis(isoamylsulfonyl)-diazomethane, bis(sec-amylsulfonyl)diazomethane,bis(tert-amylsulfonyl) diazomethane, 1-cyclohexylsulfonyl-1-(tert-butylsulfonyl)diazomethane,1-cyclohexylsulfonyl-1-(tert-amylsulfonyl)diazomethane, and1-tert-amylsulfonyl-1-(tert-butyl sulfonyl)diazomethane.

Nonionic photoacid generators can also include glyoxime derivatives suchas, for example, bis-o-(p-toluenesulfonyl)-α-dimethylglyoxime,bis-o-(p-toluenesulfonyl)-α-diphenylglyoxime,bis-o-(p-toluenesulfonyl)-α-dicyclohexyl-glyoxime,bis-o-(p-toluenesulfonyl)-2,3-pentanedione-glyoxime,bis-o-(p-toluenesulfonyl)-2-methyl-3,4-pentane-dioneglyoxime,bis-o-(n-butanesulfonyl)-α-dimethylglyoxime,bis-o-(n-butanesulfonyl)-α-diphenylglyoxime,bis-o-(n-butanesulfonyl)-α-dicyclobexylglyoxime,bis-o-(n-butanesulfonyl)-2,3-pentanedioneglyoxime,bis-o-(n-butanesulfonyl)-2-methyl-3,4-pentanedioneglyoxime,bis-o-(methanesulfonyl)-α-dimethylglyoxime,bis-o-(trifluoromethanesulfonyl)-α-dimethylglyoxime,bis-o-(1,1,1-trifluoroethanesulfonyl)-α-dimethylglyoxime,bis-o-(t-butanesulfonyl)-α-dimethylglyoxime,bis-o-(perfluorooctanesulfonyl)-α-dimethylglyoxime,bis-o-(cyclohexane-sulfonyl)-α-dimethylglyoxime,bis-o-(benzenesulfonyl)-α-dimethylglyoxime,bis-o-(p-fluorobenzenesulfonyl)-α-dimethylglyoxime,bis-o-(p-t-butylbenzenesulfonyl)-α-dimethylglyoxime,bis-o-(xylenesulfonyl)-α-dimethylglyoxime, orbis-o-(camphorsulfonyl)-α-dimethylglyoxime.

Such photoacid generators further include bissulfone derivatives suchas, for example, bisnaphthylsulfonylmethane,bistrifluoromethylsulfonylmethane, bismethylsulfonylmethane,bisethylsulfonylmethane, bispropylsulfonylmethane,bisisopropyl-sulfonylmethane, bis-p-toluenesulfonylmethane,bisbenzenesulfonylmethane,2-cyclohexyl-carbonyl-2-(p-toluenesulfonyl)propane (β-ketosulfonederivative), and 2-isopropyl-carbonyl-2-(p-toluenesulfonyl)propane(P-ketosulfone derivative).

Other classes of useful nonionic photoacid generators include disulfonoderivatives such as, for example, diphenyl disulfone and dicyclohexyldisulfone; nitrobenzyl sulfonate derivatives such as, for example,2,6-dinitrobenzyl p-toluenesulfonate and 2,4-dinitrobenzylp-toluenesulfonate; sulfonic acid ester derivatives such as, forexample, 1,2,3-tris(methanesulfonyl-oxy)benzene,1,2,3-tris(trifluoro-methanesulfonyloxy)benzene, and1,2,3-tris(p-toluenesulfonyloxy)benzene; and sulfonic acid esters ofN-hydroxyimides such as, for example, N-hydroxysuccinimidemethanesulfonate, N-hydroxy-succinimide trifluoromethanesulfonate,N-hydroxysuccinimide ethanesulfonate, N-hydroxysuccinimide1-propanesulfonate, N-hydroxysuccinimide 2-propanesulfonate,N-hydroxysuccinimide 1-pentanesulfonate, N-hydroxysuccinimide1-octanesulfonate, N-hydroxysuccinimide p-toluenesulfonate,N-hydroxysuccinimide p-methoxybenzenesulfonate, N-hydroxysuccinimide2-chloroethanesulfonate, N-hydroxysuccinimide benzenesulfonate,N-hydroxysuccinimide 2,4,6-trifluoro-benzenesulfonate,N-hydroxysuccinimide 2,4,6-trimethyl-benzenesulfonate,N-hydroxysuccinimide 2,4,6-trichloro-benzenesulfonate,N-hydroxysuccinimide 4-cyano-benzenesulfonate, N-hydroxysuccinimide1-naphthalenesulfonate, N-hydroxysuccinimide 2-naphthalenesulfonate,N-hydroxy-2-phenylsuccinimide methanesulfonate, N-hydroxymaleimidemethanesulfonate, N-hydroxymaleimide ethanesulfonate,N-hydroxy-2-phenylmaleimide methanesulfonate, N-hydroxyglutarimidemethanesulfonate, N-hydroxyglutarimide benzenesulfonate,N-hydroxyphthalimide methanesulfonate, N-hydroxyphthalimidebenzenesulfonate, N-hydroxyphthalimide trifluoromethanesulfonate,N-hydroxyphthalimide p-toluenesulfonate, N-hydroxynaphthalimidemethanesulfonate, N-hydroxynaphthalimide benzenesulfonate,N-hydroxy-5-norbornene-2,3-dicarboxylmide methanesulfonate,N-hydroxy-5-norbornene-2,3-dicarboxylmide trifluoromethanesulfonate,N-hydroxy-5-norbornene-2,3-dicarboxylmide p-toluenesulfonate,N-hydroxynaphthalimide triflate, andN-hydroxy-5-norbornene-2,3-dicarboximide perfluoro-1-butanesulfonate.

One or more nonionic photoacid generators can be present in thephotopolymerizable composition in an amount of at least 0.05 weight %and up to and including 10 weight %, or typically at least 0.1 weight %and up to and including 10 weight %, based on the total weight of theall four (a) through (d) components.

(c) Electron Donor Photosensitizers

Useful electron donor photosensitizers should be soluble in thephotocurable composition, free of functionalities that wouldsubstantially interfere with the cationic photocuring process, andcapable of light absorption (sensitivity) within the range ofwavelengths of at least 150 nm and up to and including 1000 nm.

Suitable electron donor photosensitizers initiate the chemicaltransformation of the onium salt (or other photoacid generator) inresponse to the photons absorbed from the irradiation. The electrondonor photosensitizer should also be capable of reduce the photoacidgenerator after the electron donor photosensitizer has absorbed light(that is, photoinduced electron transfer). Thus, the electron donorphotosensitizer, upon absorption of photons from irradiation, isgenerally capable of donating an electron to the photoacid generator.

For uses of the photocurable compositions in which very rapid curing(such as the curing of thin applied films of the compositions) isdesired, the electron donor photosensitizers can have an extinctioncoefficient of at least 1000 liter-mole⁻¹ cm⁻¹ and typically at least50,000 liters-mole⁻¹ cm⁻¹ at the desired irradiation wavelength usingthe photocuring process.

For example, each of the electron donor photosensitizers generally hasan oxidation potential of at least 0.4 V and up to and including 3 V vs.SCE (saturated calomel electrode), or more typically of at least 0.8 Vand up to and including 2 V vs. SCE.

In general, many different classes of compounds can be used as electrondonor photosensitizers for various reactants. Useful electron donorphotosensitizers include but are not limited to, aromatics such asnaphthalene, 1-methylnaphthalene, anthracene, 9,10-dimethoxyanthracene,benz[a]anthracene, pyrene, phenanthrene, benzo[c]phenanthrene, andfluoranthene.

Other useful electron donor photosensitizers that involve the tripletexcited state are carbonyl compounds such as thioxanthones andxanthones. Ketones including aromatic ketones such as fluorenone, andcoumarin dyes such as ketocoumarins such as those with strong electrondonating moieties (such as dialkylamino) can also be used as electrondonor photosensitizers. Other suitable electron donor photosensitizersare believed to include xanthene dyes, acridine dyes, thiazole dyes,thiazine dyes, oxazine dyes, azine dyes, aminoketone dyes, porphyrins,aromatic polycyclic hydrocarbons, p-substituted aminostyryl ketonecompounds, aminotriarylmethanes, merocyanines, squarylium dyes, andpyridinium dyes.

It is also possible to use a mixture of electron donor photosensitizersthat are chosen from the same or different classes of materials.

Various useful electron donor photosensitizers are available fromvarious commercial sources and can be readily found for use in thepresent invention.

The one or more electron donor photosensitizers can be present in thephotocurable composition in an amount of at least 0.0001 weight % and upto and including 5 weight %, and typically at least 0.001 weight % andup to and including 2 weight %, based on the total weight of components(a) through (d). In some embodiments, the electron donor photosensitizeris a pyrene, benzopyrene, perylene, or benzoperylene that is present inan amount of at least 0.05 weight % and up to and including 2 weight %,based on the total weight of components (a), (b), and (d).

(d) Metal Particles

Metal particles are present in the photocurable composition. Usuallyonly one type of metal particles is used, but it is also possible toinclude mixtures of metal particles, from the same or different classesof metals, that do not interfere with each other. These metal particlesgenerally have a net neutral charge.

Useful metal particles can be chosen from one or more classes of noblemetals, semi-noble metals, Group IV metals, or combinations thereof.Useful noble metal particles include but are not limited to, particlesof gold, silver, palladium, platinum, rhodium, iridium, rhenium,mercury, ruthenium, and osmium. Useful particles of semi-noble metalsinclude but are not limited to, particles of iron, cobalt, nickel,copper, carbon, aluminum, zinc, and tungsten. Useful particles of GroupIV metals include but are not limited to particles of tin, titanium, andgermanium. The noble metal particles such as particles of gold, silver,palladium, and platinum are particularly useful, and the semi-nobleparticles of nickel and copper are also particularly useful. Tinparticles are particularly useful in the Group IV metal class. In manyembodiments, silver or copper particles are used in the photocurablecomposition as “seed” metal particles of electroless plating methods.

The metal particles useful in the present invention can be coated withsurfactants, polymers, or carbon. The carbon used for coating metalparticles can be amorphous, sp2 hybridized, or graphene-like in nature.Such carbon can be used to prevent aggregation of metal particles andprovide improved dispersibility in the photocurable composition.

The metal particles can be dispersed in various organic solvents and canhave improved dispersibility in the presence of the other essentialcomponents of the photocurable composition, such as multifunctionalpolymeric epoxy materials or in the presence of optional components suchas multifunctional acrylate resins described below. The methods used todisperse the metal particles include but are not limited to,ball-milling, magnetic stirring, high speed homogenization, highpressure homogenization, and ultrasonication.

The metal particles can be present in the photopolymerizable compositionas individual particles, but in many embodiments, the metal particlesare present as agglomerations of two or more metal particles. Such metalparticles can be present in any geometric shape including but notlimited to, spheres, rods, prisms, cubes, cones, pyramids, wires,flakes, platelets, and combinations thereof, and they can be uniform ornon-uniform in shapes and sizes. The average particle size of individualand agglomerated metal particles can vary from at least 0.01 μm and upto and including 25 μm, or more likely of at least 0.02 μm and up to andincluding 5 μm. Although the size of the metal particles is notparticularly limited, optimal benefits can be achieved using metalparticles as individual particles or agglomerates, having an averageparticle size of at least 0.02 μm and up to and including 10 μm. Theparticle size distribution is desirably narrow as defined as one inwhich greater than 50%, or typically at least 75%, of the particles havea particle size in the range of 0.2 to 2 times the average particlesize. The average particle size (same as mean particle size) can bedetermined from the particle size distribution that can be determinedusing any suitable procedure and equipment including that available fromCoulter or Horiba and the appropriate mathematical calculations usedwith that equipment.

Useful metal particles can be obtained from various commercial sources,or they can be derived from various metal salts or complexes and knownreduction and isolation processes prior to use in the practice of thisinvention. Some commercial metal particles can be obtained for examplefrom Novacentrix.

The metal particles are generally present in the photocurablecomposition in an amount of at least 0.1 weight % and up to andincluding 50 weight % or more typically at least 1 weight % and up toand including 30 weight %, based on the total weight of components (a)through (d).

(e) Free Radically Polymerizable Compounds

The photocurable compositions can also contain one or morefree-radically polymerizable compounds to provide free-radicallypolymerizable functionality, including ethylenically unsaturatedpolymerizable monomers, oligomers, or polymers such as mono-functionalor multi-functional acrylates (also includes methacrylates). Suchfree-radically polymerizable compounds comprise at least oneethylenically unsaturated polymerizable bond and they can comprise twoor more of these unsaturated moieties that are capable of undergoingaddition (or free radical) polymerization. Such free radicallypolymerizable materials include mono-, di-, or poly-acrylates andmethacrylates including but not limited to, methyl acrylate, methylmethacrylate, ethyl acrylate, isopropyl methacrylate, n-hexyl acrylate,stearyl acrylate, allyl acrylate, glycerol diacrylate, glyceroltriacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate,triethylene glycol dimethacrylate, 1,3-propanediol diacrylate,1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate,1,6-hexanediol diacrylate, neopentyl glycol diacrylate, neopentyl glycoldimethacrylate, trimethylolpropane triacrylate, 1,2,4-butanetrioltrimethacrylate, 1,4-cyclohexanediol diacrylate, pentaerythritoltriacrylate, pentaerythritol tetraacrylate, pentaerythritoltetramethacrylate, dipentaetrythritol hexaacrylate, sorbitolhexaacrylate, bis[1-(2-acryloxy)]-p-ethoxyphenyldimethylmethane,bis[1-(3-acryloxy-2-hydroxy)]-p-propoxyphenyldimethylmethane, andtris-hydroxyethyl-isocyanurate trimethacrylate; the bis-acrylates andbis-methacrylates of polyethylene glycols having a molecular weight offrom 200 to and including 500, co-polymerizable mixtures of acrylatemonomers such as those described in U.S. Pat. No. 4,652,274 (Boettcheret al.) and acrylate oligomers such as those described in U.S. Pat. No.4,642,126 (Zader et al.); and vinyl compounds such as styrene andstyrene derivatives, diallyl phthalate, divinyl succinate, divinyladipate, and divinyl phthalate. Mixtures of two or more of these freeradically polymerizable materials can be used if desired.

Such materials can be purchased from a number of commercial sources orprepared using known synthetic methods and starting materials.

Although the amount of the one or more free radically polymerizablematerials is not particularly limited, they can be present in thephotopolymerizable compositions in an amount of at least 20 weight % andup to and including 75 weight % or typically of at least 40 weight % andup to and including 60 weight %, based on the total weight of allcomponents of the photocurable composition and can be optimized based onthe desired properties of composition solubility and mechanical strengthof the photocured composition.

(f) Free Radical Photoinitiators

If the (e) component is present, one or more free radicalphotoinitiators are also present in the photocurable compositions togenerate free radicals in the presence of the free-radicallypolymerizable compounds. Such free radical photoinitiators include anycompound that is capable of generating free radicals upon exposure tophotopolymerizing radiation used in the practice of this invention suchas ultraviolet or visible radiation. For example, free radicalphotoinitiators can be selected from triazine compounds, thioxantonecompounds, benzoin compounds, carbazole compounds, diketone compounds,sulfonium borate compounds, diazo compounds, and biimidazole compounds,and others that would be readily apparent to one skilled in the art.Mixtures of such compounds can be selected from the same or differentclasses.

Also useful are benzophenone compounds such as benzophenone, benzoylbenzoate, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxylbenzophenone, acrylated benzophenone,4,4′-bis(dimethylamino)benzophenone and4,4′-bis(diethylamino)benzophenone, anthraquinone compounds, andacetophenone compounds such as 2,2′-diethoxyacetophenone,2,2′-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone,p-t-butyltrichloroacetophenone, p-t-butyldichloroacetophenone,benzophenone, 4-chloroacetophenone, 4,4′-dimethylaminobenzophenone,4,4′-dichlorobenzophenone, 3,3′-dimethyl-2-methoxybenzophenone,2,2′-dichloro-4-phenoxyacetophenone,2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one, and2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one. Furtheruseful compounds of this type are described for example in U.S. Pat. No.7,875,416 (Park et al.).

Many of such free radical photoinitiators can be obtained from variouscommercial sources.

Such free radical photoinitiators are generally present in thephotocurable composition in an amount of at least 0.1 weight % and up toand including 10 weight %, or typically at least 1 weight % and up toand including 5 weight %, based on the total weight of all components ofthe photocurable composition.

It is also possible include conductive nano-oxides and conductivenano-carbon materials such as nano-tubes, nano-graphene, and buckyballs. Conductive nano-oxides include but are not limited to, indium tinoxide, antimony oxide, antimony tin oxides, indium oxide, zinc oxide,zinc aluminum oxide, and mixtures thereof.

It can be useful to include one or more hydroxy-containing materials,including polyols, in the photocurable composition as charge transferagents to aid in the photopolymerization process. The term “polyol”refers to an organic compound having two or more primary or secondaryaliphatic hydroxy groups in the molecule. Each hydroxy (or hydroxyl)group in a hydroxy-containing material is directly bonded to anon-aromatic carbon atom in the molecule. When used, thehydroxy-containing materials can be in liquid or solid form and have anorganic nature. Any of the hydroxyl groups can be terminally situated,or pendant from a homopolymer or copolymer backbone.

Addition of vinyl ether compounds as chain transfer agents to thephotocurable compositions can also be desirable to further increasephotopolymerization rates or ensure desired physical properties in thefinal photocured patterned material. Examples of useful vinyl ethercompounds include but are not limited to, Rapi-Cure™ DVE-3(triethyleneglycol divinylether), Rapi-Cure™ CHVE (1,4-cyclohexanedimethanoldivinylether), and Rapi-Cure™ HBVE (butanediolmonovinylether), all available from Ashland Inc.).

The photocurable compositions can also contain suitable adjuvants (oradditives) such as accelerators, inhibitors, absorbers, stabilizers,pigments, dyes, UV absorbers, viscosity modifiers, flow improvers,surface tension depressants and wetting aids, antioxidants, surfactants,and other ingredients well known to those skilled in the art.

Photocurable compositions are generally prepared as patterned materialsfor coating, printing, or other means of application to the substrate ofthis invention by simply admixing, under “safe light” conditions withinsuitable inert organic solvents that do not react appreciably with anycomponents incorporated therein. Examples of suitable inert solventsinclude but are not limited to, acetone, dichloromethane, isopropenol,Dowanol PM, 1-methoxy-2-propanol, ethylene glycol, and mixtures thereof.When one or more components to be used are in liquid form, thosecomponents can act as the “solvent” for the photocurable composition, orused in combination with one or more inert organic solvents.Solvent-free photocurable compositions can be prepared by simplydissolving, dispersing, and mixing the essential components (a) through(d) and any optional components with or without the use of mild heatingto facilitate dissolution or dispersion.

When inert organic solvents are used, they can be present in an amountof at least 1 weight % and up to and including 70 weight % or at least20 weight % and up to and including 50 weight %, based on the totalweight of the components (a) through (d) described above.

Upon suitable photocuring or thermal curing conditions, the articledescribed above can comprise a patterned material comprising anelectrically-conductive metal and a photocured or thermally curedcomposition, all disposed in a patternwise fashion on the dried primerlayer of the substrate. At least a portion of the pattern of patternablematerial comprises lines having an average line width of less than 15μm. Such patterned material thus can comprise particles of gold, silver,copper, palladium, or platinum dispersed within the photocured orthermally cured composition that has been derived from the correspondingphotocurable or thermally curable composition.

Methods for Making Patterns Including Electrically-Conductive Patterns

A first method is used to provide a primed article with a patternedmaterial, including providing a transparent polymeric substrate thatcomprises a transparent polymer support (as described above) and a driedprimer layer (as described above), and then providing a pattern of apatternable material (as described above) directly onto the dried primerlayer. As noted above, this pattern can be provided by direct contact ofthe dried primer layer with a relief printing member (such as aflexographic printing member) as described herein, which relief printingmember carries the patterned material on the upper surface of the reliefimage that is typically formed in an elastomeric material. Gravureprinting and intaglio printing are other means for applying a pattern ofa patternable material onto the dried primer layer.

Moreover, it is desirable that at least a portion of the pattern ofpatterned material so provided comprises lines having an average linewidth of less than 15 μm, and such portion of the patterned materialwill be present in what will eventually be the touch screen region ofthe primed article (as opposed to an electrode regions or BUS region).Such patterned material can comprise an electrically-conductive metal orelectrically-conductive metal precursor as described above, and thepatterned material can comprise a photocurable or thermally curablecomposition, either of which comprises an electrically-conductive metalor an electrically-conductive metal precursor.

It should also be understood especially from the description ofparticular manufacturing embodiments described below, that the same ordifferent patterned material can be applied to opposing supporting sidesof the substrate, particularly if the substrate comprises a dried primerlayer on both supporting sides of the support. Such primed and patternedarticles can be considered “duplex” since they have a dried primer layerand pattern material on both sides of the support (including transparentpolymer supports).

In particularly desirable embodiments in which the patterned materialcomprises a photocurable or thermally curable composition, the patternedmaterial is then subjected to curing conditions and apparatus, on one orboth sides of the substrate.

For example, photocuring can be achieved by irradiating the patternedmaterial with radiant energy such as ultraviolet light as describedabove. Desirable photocuring can be achieved using UV or visibleirradiation having a wavelength of at least 184.5 nm to and including700 nm and at intensity of at least 1 mJ/cm² and up to and including1000 mJ/cm² or more typically of at least 1 mJ/cm² and up to andincluding 800 mJ/cm².

At least a portion of the resulting cured pattern of patterned material(for example, precursor electrically-conductive material) can comprisefine lines of cured material having an average line width of less than15 μm in that portion. In many embodiments, the entire pattern is curedin this manner.

At least a portion, and generally all, of the cured pattern of precursorelectrically-conductive material can be converted to a pattern ofelectrically-conductive material comprises electrically-conductive finelines as described above. By “precursor electrically-conductivematerial” refers to a composition that can be treated chemically,physically, or electrically to render the materialelectrically-conductive. Some embodiments of such “precursor” materialsare compositions comprising “seed” metals described below.

When the patterned material in such embodiments comprises anelectrically-conductive metal or an electrically-conductive metalprecursor, for example, wherein the electrically-conductive metalcomprises seed metal particles, the seed metal particles in the patternof patterned material on the substrate can be electrolessly metal platedusing conditions and electroless plating reagents that are known in theart, some of which details are described below. Multiple patternscontaining seed metal particles can be created in this manner especiallywhen the transparent polymeric substrate containing the dried primerlayer is a continuous web as illustrated below and shown in FIG. 1.

In such embodiments, a plurality of individual patterns of aphotocurable or thermally curable composition are provided on atransparent polymeric substrate in the form of a continuous web, whichphotocurable or thermally curable composition is a precursorelectrically-conductive material containing seed metal particles,applied directly on the dried primer layer in a plurality of individualportions of the continuous web. Such continuous web can have anintegrated transmittance of at least 88% or at least 95%, and comprisesthe dried primer layer (as described above) on a transparent polymersupport that can be a transparent polyester support (as describedabove).

In this manner, a plurality of precursor articles described herein canbe prepared for use immediately after production or at a later time. Forexample, a plurality of precursor articles can be formed on a continuousweb of the primed substrate of this invention that has been provided inroll form, and then is wound up in roll form containing first, second,and optional additional multiple cured patterns. Each of the pluralityof individual patterns of photocurable or thermally curable compositionsin the patterned material is cured as noted above to form a plurality ofindividual cured patterns in the plurality of individual portions on thecontinuous web, which individual cured patterns contain the seed metalparticles.

Such plurality of individual cured patterns can then be electrolesslyplated as described below immediately after curing or sometime later andoptionally at a different location, using the same or differentelectroless plating baths and conditions.

The resulting product articles contain one or moreelectrically-conductive patterns on one or both sides of the substrate,which electrically-conductive patterns can comprise the fine lineshaving an average line width of less than 15 μm, and can be arranged ina touch region of an electrically-conductive article or display device.Particularly useful devices of this type comprise a transparentelectrically-conductive film having an integrated transmittance of atleast 88% and the dried primer layer of the substrate (as describedabove) is directly disposed on a transparent polymer support, such as apolyester support.

More details regarding large scale manufacturing and use of primedarticles to provide electrically-conductive articles and devices are nowconsidered.

A primed article of this invention can be used individually as a singleelement, or as a continuous web (for example, for roll-to-rollprocesses) having multiple portions of patterns of patterned materialsdirectly disposed on the dried primer layer (on one or both supportingsides of the substrate). Such continuous web can be processed to applypatterned material in coating stations and then advanced throughexposure (curing) stations, or the exposure (curing) device can bepassed over multiple patterns of patterned material of the continuousweb. The same or different photocurable compositions can be used in thepatterned materials (for example, printed) on both supporting sides ofthe substrate whether it is in the form of a single element orcontinuous web. In many embodiments, different conductive metal patternsare formed on opposing supporting sides of the substrate (or continuousweb).

As noted above, the patterned material can be applied in a patternwisemanner using any suitable means for application, but flexographicprinting using flexographic printing members are particularly useful.

After application of the patterned material onto a substrate, any inertorganic solvents can be removed by a drying or pre-baking procedure thatdoes not adversely affect the remaining components or prematurely causepolymerization. Useful drying conditions can be as low as roomtemperature for as little as 5 seconds and up to and including severalhours depending upon the manufacturing process. In most processes, suchas roll-to-roll processes described below, the drying conditions can beat high enough temperatures to remove at least 90% of the inert organicsolvent within at least 1 second.

Any applied pattern of the patterned material can comprise a grid oflines (or other shapes including circles or an irregular network) havingan average thickness (or width) of at least 0.2 μm and up to andincluding 20 μm, or typically of at least 2 μm and up to and including15 μm, and the optimal dry thickness (or width) can be tailored for theintended use of the resulting uniform photocured layer, which generallyhas about the same dry thickness (or width) as the grid lines of thenon-photocured patterned material.

Thus, the present invention provides articles comprising a substrate andpatterns of the patterned material, wherein such articles can beconsidered “precursor” articles, meaning that they are the firstarticles produced in methods used to provide conductive articles.

In some embodiments, the same or different photocurable or thermallycurable composition can be applied in a suitable manner on bothsupporting sides of the substrate to form various features for eachcurable pattern on “duplex” or dual-sided precursor articles, and themultiple cured patterns can have the same or different seed metalparticles that are gold particles, silver particles, copper particles,palladium particles, or platinum particles.

In many embodiments, a pattern of the photocurable or thermally curablecomposition is applied on one or both (opposing) supporting sides of thesubstrate (for example as a roll-to-roll continuous web) using a reliefprinting member such as elastomeric printing members derived fromflexographic printing plate precursors, many of which are known in theart and some are commercially available, for example as the Cyrel®Flexographic Photopolymer Plates from DuPont and the Flexcel SR and NXFlexographic plates from Eastman Kodak Company.

Particularly useful relief printing members are derived fromflexographic printing plate precursors and flexographic printing sleeveprecursors, each of which can be appropriately imaged (and processed ifneeded) to provide the relief images for “printing” or applying asuitable pattern.

For example, useful flexographic printing member precursors aredescribed in U.S. Pat. No. 7,799,504 (Zwadlo et al.) and U.S. Pat. No.8,142,987 (Ali et al.) and U.S. Patent Application Publication2012/0237871 (Zwadlo). The relief image layer can be different forproviding different patterns of patterned materials to the same oropposing supporting sides of the substrate. In other embodiments, theelastomeric relief element is provided from a direct (or ablation)laser-engraveable elastomer relief element precursor, with or withoutintegral masks, as described for example in U.S. Pat. No. 5,719,009(Fan), U.S. Pat. No. 5,798,202 (Cushner et al.), U.S. Pat. No. 5,804,353(Cushner et al.), U.S. Pat. No. 6,090,529 (Gelbart), U.S. Pat. No.6,159,659 (Gelbart), U.S. Pat. No. 6,511,784 (Hiller et al.), U.S. Pat.No. 7,811,744 (Figov), U.S. Pat. No. 7,947,426 (Figov et al.), U.S. Pat.No. 8,114,572 (Landry-Coltrain et al.), U.S. Pat. No. 8,153,347 (Vereset al.), U.S. Pat. No. 8,187,793 (Regan et al.), and U.S. PatentApplication Publications 2002/0136969 (Hiller et al.), 2003/0129530(Leinenback et al.), 2003/0136285 (Telser et al.), 2003/0180636 (Kangaet al.), and 2012/0240802 (Landry-Coltrain et al.).

When the noted elastomeric relief elements are used in the presentinvention, the patterned material can be applied in a suitable manner tothe uppermost relief surface (raised surface) in the relief printingmember. Application can be accomplished using several suitable means andit is desirable that as little as possible is coated onto the sides(slopes) or recesses of the relief depressions. Thus, it is desirablethat as much as possible of the patterned material is applied only tothe uppermost relief surface. Anilox roller systems or other rollerapplication systems, especially low volume Anilox rollers, below 2.5billion cubic micrometers per square inch (6.35 billion cubicmicrometers per square centimeter) and associated skive knives can beused. Optimum metering of the patterned material onto the uppermostrelief surface can be achieved by controlling viscosity or thickness, orchoosing an appropriate application means.

The patterned material can be fed from an Anilox or other roller inkingsystem in a measured amount for each printed pattern. In one embodiment,a first roller can be used to transfer the patterned material from an“ink” pan or a metering system to a meter roller or Anilox roller. Thepatterned material is generally metered to a uniform thickness when itis transferred from the Anilox roller to a printing plate cylinder. Whenthe substrate (for example, continuous web) is moved through theroll-to-roll handling system from the printing plate cylinder to animpression cylinder, the impression cylinder applies pressure to theprinting plate cylinder that transfers an image from a relief printingmember to the substrate.

After the patterned material has been applied to the uppermost reliefsurface (or raised surface) of the relief printing member, it can beuseful to remove at least 25 weight % of any inert organic solventsincluded in the patterned material to form a more viscous deposit on theuppermost relief surface of the relief image. This removal of inertorganic solvents can be achieved in any manner, for example using jetsof hot air, evaporation at room temperature, or heating in an oven at anelevated temperature, or other means known in the art for removing asolvent.

Once the one or more patterns are disposed on the dried primer layer ofthe substrate (for example, as a continuous web), the patterned materialin the resulting precursor article can be cured for example byirradiation with suitable radiation as described above from a suitablesource such as a fluorescent lamp or LED to provide one or more curedpatterns on the substrate. The irradiation system used to generatesuitable radiation can consist of one or more ultraviolet lamps forexample in the form of 1 to 50 discharge lamps, for example, xenon,metallic halide, metallic arc (such as a low, medium or high pressuremercury vapor discharge lamps having the desired operating pressure froma few millimeters to about 10 atmospheres). The lamps can includeenvelopes capable of transmitting light of a wavelength of at least 190nm and up to and including 700 nm or typically at least 240 nm and up toand including 450 nm. Typical lamps that can be employed for providingultraviolet radiation are, for example, medium pressure mercury arcs,such as the GE H3T7 arc and a Hanovia 450 W arc lamp. Photocuring can becarried out using a combination of various lamps, some of or all ofwhich can operate in an inert atmosphere. When using UV lamps, theirradiation flux impinging upon the substrate (or applied layer orpattern) can be at least 0.01 watts/inch² (0.00155 watts/cm²) to effectsufficient rapid photocuring of the applied patterned material within 1to 20 seconds in a continuous manner, for example in a roll-to-rolloperation.

An LED irradiation device to be used in the photocuring station can havean emission peak wavelength of 350 nm or more. The LED device caninclude two or more types of elements having different emission peakwavelengths greater than or equal to 350 nm. A commercial example of anLED device that has an emission peak wavelength of 350 nm or more andhas an ultraviolet light-emitting diode (UV-LED), is NCCU-033 that isavailable from Nichia Corporation.

The result of such irradiation of a precursor article is an intermediatearticle comprising the substrate (for example, individual sheets or acontinuous web) and having thereon one or more cured patterns (forexample, each containing suitable seed metal particles) on one or bothsupporting sides of the substrate. In some embodiments of the precursorarticles, the multiple curable patterns and cured patterns can be formedusing the same photocurable or thermally curable composition. Suchphotocurable composition can comprise a free radical curablecomposition, an acid catalyzed composition, or both a free radicalcurable composition and an acid catalyzed curable composition, all asdescribed above.

The resulting intermediate articles can be used in this form for someapplications, but in most embodiments, they are further processed toincorporate an electrically-conductive metal on the one or more(multiple) cured patterns, each of which can include the seed metalparticles for electroless metal plating procedures. For example, theseed metal particles can be the metal particles identified above ascomponent (d), for example gold particles, silver particles, copperparticles, palladium particles, or platinum particles, or mixturesthereof.

One useful method according to the present invention uses multipleflexographic printing plates (for example, prepared as described above)in a stack in a printing station wherein each stack has its own printingplate cylinder so that each flexographic printing plate is used to printindividual portions of patterned materials on a substrate, such as usingthe stack of printing plates to print patterns of patterned material inmultiple portions on one or both supporting sides of a substrate web(such a polymeric continuous web). The same or differentphotopolymerizable composition can be “printed” or applied to thesemultiple portions on the substrate using the multiple flexographicprinting plates.

In other embodiments, a central impression cylinder can be used with asingle impression cylinder mounted on a printing press frame. As thesubstrate enters the printing press frame, it is brought into contactwith the impression cylinder and the appropriate pattern is printed withthe patterned material such as a photocurable composition.Alternatively, an in-line flexographic printing process can be utilizedin which the printing stations are arranged in a horizontal line and aredriven by a common line shaft. The printing stations can be coupled toexposure stations, cutting stations, folders, and other post-processingequipment. A skilled worker could readily determine other usefulconfigurations of equipment and stations using information that isavailable in the art. For example, an in-the-round imaging process isdescribed in WO 2013/063084 (Jin et al.).

The intermediate article prepared at this stage containing one or morecured patterns (or portions) containing seed metal particles can beimmediately immersed in an aqueous-based electroless metal plating bathor solution, or the intermediate article can be stored with just thecured patterns for use at a later time.

The intermediate article can be contacted with an electroless platingmetal that is the same as or different from the corresponding seed metalparticles described above. In most embodiments, the electroless platingmetal is a different metal from the corresponding seed metal particles.

Any metal that will likely electrolessly “plate” on the cured patternsof corresponding seed metal particles can be used at this point, but inmost embodiments, the electroless plating metal can be for examplecopper(II), silver(I), gold(IV), palladium(II), platinum(II),nickel(II), chromium(II), and combinations thereof. Copper(II),silver(I), and nickel(II) are particularly useful electroless platingmetals.

The one or more electroless plating metals can be present in theaqueous-based electroless plating bath or solution in an amount of atleast 0.01 weight % and up to and including 20 weight % based on totalsolution weight.

Electroless plating can be carried out using known temperature and timeconditions, as such conditions are well known in various textbooks andscientific literature. It is also known to include various additivessuch as metal complexing agents or stabilizing agents in theaqueous-based electroless plating solutions. Variations in time andtemperature can be used to change the metal electroless platingthickness or the metal electroless plating deposition rate.

A useful aqueous-based electroless plating solution or bath is anelectroless copper(II) plating bath that contains formaldehyde as areducing agent. Ethylenediaminetetraacetic acid (EDTA) or salts thereofcan be present as a copper complexing agent. For example, copperelectroless plating can be carried out at room temperature for severalseconds and up to several hours depending upon the desired depositionrate and plating rate and plating metal thickness.

Other useful aqueous-based electroless plating solutions or bathscomprise silver(I) with EDTA and sodium tartrate, silver(I) with ammoniaand glucose, copper(II) with EDTA and dimethylamineborane, copper(II)with citrate and hypophosphite, nickel(II) with lactic acid, aceticacid, and a hypophosphite, and other industry standard aqueous-basedelectroless baths or solutions such as those described by Mallory et al.in Electroless Plating: Fundamentals and Applications 1990.

After the electroless plating procedure to provide a conductive metalpattern on one or more cured portions on one or opposing supportivesides of the substrate (such as a continuous web), the resulting productarticle is removed from the aqueous-based electroless plating bath orsolution and can again be washed using distilled water or deionizedwater or another aqueous-based solution to remove any residualelectroless plating chemistry. At this point, the electrolessly platedmetal is generally stable and can be used for its intended purpose.

In some embodiments, the resulting product article can be rinsed orcleaned with water at room temperature as described for example in[0048] of WO 2013/063183 (Petcavich), or with deionized water at atemperature of less than 70° C. as described in [0027] of WO 2013/169345(Ramakrishnan et al.).

Thus, this method provides a product article comprising a substratecomprising a dried primer layer as described above and having disposedthereon electrically-conductive patterns comprising at least some finelines having an average line width of less than 15 μm on one or bothsupporting sides of the substrate.

To change the surface of the electroless plated metal for visual ordurability reasons, it is possible that a variety of post-treatments canbe employed including surface plating of still at least another (thirdor more) metal such as nickel, palladium, or silver on the electrolesslyplated metal (this procedure is sometimes known as “capping”), or thecreation of a metal oxide, metal sulfide, or a metal selenide layer thatis adequate to change the surface color and scattering propertieswithout reducing the conductivity of the electrolessly plated (second)metal. Depending upon the metals used in the various capping proceduresof the method, it may be desirable to treat the electrolessly platedmetal with another seed metal catalyst in an aqueous-based seed metalcatalyst solution to facilitate deposition of additional metals.

In addition, multiple treatments with aqueous-based electroless metalplating solutions can be carried out in sequence, using the same ordifferent conditions. Sequential washing or rinsing steps can be alsocarried out where appropriate at room temperature or a temperature lessthan 70° C.

Further, the electroless plating procedures can be carried out multipletimes, in sequence, using the same or different electroless platingmetal and the same or different electroless plating conditions.

Thus, in some embodiments of the method for providing a product articleof this invention, the method comprises:

providing a continuous web of a transparent polymeric substrate of anyof the embodiments described above,

forming a photocurable or thermally curable pattern on at least a firstportion of the continuous web (directly on the dried primer layer) usinga photocurable or thermally curable composition as described above, forexample using a flexographic printing member,

curing the photocurable or thermally curable pattern in a suitablemanner (as described above) to form a photocured or thermally curedpattern on the first portion, and

electrolessly plating the photocured r thermally cured pattern on thefirst portion with an electrically conductive metal, using electrolessplating procedures described above.

Embodiments of this method can be carried out on a single supportingside of the substrate, or on opposing supporting sides of the substrateto provide the same or different electrically-conductive patterns.

In still other embodiments, a method of this invention can be used toprovide a plurality of electrically-conductive metal patterns,comprises:

providing a continuous web according to this invention comprisingmultiple photocured patterns in respective portions, each photocuredpattern being provided by irradiation of a photocurable or thermallycurable composition as described above,

treating the continuous web comprising multiple photocured or thermallycured patterns with an electroless metal plating solution to providemultiple electrolessly plated metal patterns on the continuous web inthe respective portions, and

optionally, further treating the multiple electrolessly plated metalpatterns with a capping metal to provide multiple capped electricallyconductive patterns on the continuous web.

This method can be taken further by:

forming individual electrically-conductive articles from the continuousweb comprising multiple capped electrically-conductive patterns, and

assembling the individual electrically-conductive articles into the sameor different individual devices such as display devices having touchscreen displays.

Such method embodiments can be carried out on both supporting sides ofthe substrates using the same or different photocurable or thermallycurable compositions.

Useful product articles prepared according to the present invention canbe formulated particularly into capacitive touch screen sensors thatcomprise suitable conductive grid lines, electrodes (or BUS regions),electrical leads, and electrical connectors. For example, the electrodesand tail can be formed by printing the pattern materials andelectrolessly plating the printed patterns.

Some details of useful methods and apparatus for carrying out thepresent invention are described for example in WO 2013/063183(Petcavich), WO 2013/169345 (Ramakrishnan et al.). Other details of auseful manufacturing system for preparing conductive articles especiallyin a roll-to-roll manner are provided in PCT/US/062366 (filed Oct. 29,2012 by Petcavich and Jin), the disclosure of which is incorporatedherein by reference.

An additional system of equipment and step features that can be used incarrying out the present invention is described in U.S. Ser. No.14/146,867 (filed Jan. 3, 2014 by Shifley), which is incorporated hereinby reference for any details that are pertinent to the presentinvention.

Referring to FIG. 1, it shows a schematic side view of a flexographicprinting system 100 that can be used in embodiments of the method of thepresent invention for roll-to-roll printing a photocurable or thermallycurable composition on both (opposing) supportive sides of a substrate150 that can comprise a dried primer layer disposed directly on asupport. Substrate 150 is fed as a continuous web from supply roll 102to take-up roll 104 through flexographic printing system 100. Substrate150 has a first supporting side 151 and a second supporting side 152.

Flexographic printing system 100 includes two print modules 120 and 140that are configured to print on the first supporting side 151 ofsubstrate 150, as well as two print modules 110 and 130 that areconfigured to print on the second (opposing) supporting side 152 ofsubstrate 150. The continuous web of substrate 150 travels overall inroll-to-roll direction 105 (left to right in FIG. 1). However, variousrollers 106 and 107 are used to locally change the direction of thecontinuous web of the substrate as needed for adjusting web tension,providing a buffer, and reversing a supporting side for printing. Inparticular, print module 120 roller 107 serves to reverse the localdirection of the continuous web of substrate 150 so that it is movingsubstantially in a right-to-left direction.

Each of the print modules 110, 120, 130, 140 can include some similarapparatus components including a respective plate cylinder 111, 121,131, 141, on which is mounted a respective flexographic printing plate112, 122, 132, 142, respectively. Each flexographic printing member(flexographic printing plate) 112, 122, 132, 142 has raised features 113defining an image pattern to be printed on the substrate 150. Each printmodule 110, 120, 130, 140 also includes a respective impression cylinder114, 124, 134, 144 that is configured to force a supporting side of thesubstrate 150 into contact with the corresponding flexographic printingmember 112, 122, 132, 142.

With reference to the rotation directions of the different components ofthe print modules 110, 120, 130, 140, it is noted that the impressioncylinders 124 and 144 of print modules 120 and 140 (for printing onfirst side 151 of substrate 150) rotate counter-clockwise in the viewshown in FIG. 1, while the impression cylinders 114 and 134 of printmodules 110 and 130 (for printing on second side 152 of substrate 150)rotate clockwise in this view.

Each print module 110, 120, 130, 140 also includes a respective Aniloxroller 115, 125, 135, 145 for providing the patterned material to thecorresponding flexographic printing member (flexographic printing plate)112, 122, 132, 142. As is well known in the printing industry, an Aniloxroller is a hard cylinder, usually constructed of a steel or aluminumcore, having an outer surface containing millions of very fine dimples,known as cells. Transfer of the patterned material would be readilypossible using the Anilox roller. In some embodiments, some or all ofthe print modules 110, 120, 130, 140 also include respective UV curingstations 116, 126, 136, 146 for curing the printed patternable materialonto substrate 150.

Some embodiments of product articles and devices that can be prepared byembodiments of the present invention are shown in FIGS. 2-5.

FIG. 2 shows a high-level system diagram for an apparatus (or device)300 having a touch screen 310 including a display device 320 and a touchsensor 330 that overlays at least a portion of a viewable area ofdisplay device 320. Touch sensor 330 senses touch and conveys electricalsignals (related to capacitance values for example) corresponding to thesensed touch to a controller 380. Touch sensor 330 is an example of anarticle that can be printed on both supporting sides by the flexographicprinting system 100 including print modules that incorporate embodimentsof flexographic printing (inking) systems described above.

FIG. 3 shows a schematic side view of a touch sensor 330. Transparentsubstrate 340 of the present invention, for example a transparentpolyester such as transparent poly(ethylene terephthalate), has a firstconductive pattern 350 printed on a first supporting side 341, and asecond conductive pattern 360 printed on a second (opposing) supportingside 342. The length and width of the transparent substrate 340, whichis cut from the take-up roll 104 (FIG. 1), is not larger than theflexographic printing plates (or flexographic printing members) 112,122, 132, 142 of flexographic printing system 100 (FIG. 1), but it couldbe smaller than the flexographic printing plates (or flexographicprinting members) 112, 122, 132, 142. Optionally, the first conductivepattern 350 and the second conductive pattern 360 can be plated using aplating process for improved electrical conductivity after flexographicprinting and curing of the patterns or patterned material. A patternedmaterial can be used to provide the noted electrically-conductivepatterns 350 and 360 according to the method of this invention.

FIG. 4 shows an example of electrically-conductive pattern 350 that canbe printed on first supporting side 341 (FIG. 3) of substrate 340 (FIG.3) using one or more print modules such as print modules 120 and 140 offlexographic printing system (FIG. 1). Electrically-conductive pattern350 includes a grid 352 including grid columns 355 of intersecting finelines 351 and 353 that are connected to an array of channel pads 354.Interconnect lines 356 connect the channel pads 354 to the connectorpads 358 that are connected to controller 380 (FIG. 2).Electrically-conductive pattern 350 can be printed by a single printmodule 120 in some embodiments. However, because the optimal printconditions for fine lines 351 and 353 (for example, having line widthson the order of 4 to 8 μm) are typically different than for printing thewider channel pads 354, connector pads 358, and interconnect lines 356,it can be advantageous to use one print module 120 for printing the finelines 351 and 353 and a second print module 140 for printing the widerfeatures. Furthermore, for clean intersections of fine lines 351 and 353it can be further advantageous to print and cure one set of fine lines351 using one print module 120, and to print and cure the second set offine lines 353 using a second print module 140, and to print the widerfeatures using a third print module (not shown in FIG. 1) configuredsimilarly to print modules 120 and 140.

FIG. 5 shows an example of electrically-conductive pattern 360 that canbe printed on second supporting side 342 (FIG. 3) of substrate 340 (FIG.3) using one or more print modules such as print modules 110 and 130 offlexographic printing system 100 (FIG. 1). Electrically-conductivepattern 360 includes a grid 362 including grid rows 365 of intersectingfine lines 361 and 363 that are connected to an array of channel pads364. Interconnect lines 366 connect the channel pads 364 to theconnector pads 368 that are connected to controller 380 (FIG. 2). Insome embodiments, electrically-conductive pattern 360 can be printed bya single print module 110 (FIG. 1). However, because the optimal printconditions for fine lines 361 and 363 (for example, having line widthson the order of 4 to 8 μm) are typically different than for the widerchannel pads 364, connector pads 368, and interconnect lines 366, it canbe advantageous to use one print module 110 (FIG. 1) for printing thefine lines 361 and 363 and a second print module 130 (FIG. 1) forprinting the wider features. Furthermore, for clean intersections offine lines 361 and 363 it can be further advantageous to print and cureone set of fine lines 361 using one print module 110 (FIG. 1), and toprint and cure the second set of fine lines 363 using a second printmodule 130 (FIG. 1), and to print the wider features using a third printmodule (not shown in FIG. 1) configured similarly to print modules 110and 130 (FIG. 1).

Alternatively, in some embodiments electrically-conductive pattern 350(FIG. 4) can be printed using one or more print modules configured likeprint modules 110 and 130 (FIG. 1), and electrically-conductive pattern360 (FIG. 5) can be printed using one or more print modules configuredlike print modules 120 and 140 (FIG. 1).

With reference to FIGS. 2-5, in operation of touch screen 310,controller 380 can sequentially electrically drive grid columns 355 viaconnector pads 358 and can sequentially sense electrical signals on gridrows 365 via connector pads 368. In other embodiments, the driving andsensing roles of the grid columns 355 and the grid rows 365 can bereversed.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. A composition comprising a mixture of a first polymer latex and asecond polymer latex,

wherein the first polymer latex comprises a first polymer and a firstsurfactant such that a dried coating of the first polymer latex has asurface polarity of at least 50%, and

wherein the second polymer latex comprises a second polymer and a secondsurfactant such that a dried coating of the second polymer latex has asurface polarity of less than or equal to 27%, and

wherein a dried coating of the composition has a surface polarity of atleast 15% and up to and including 50%.

2. The composition of embodiment 1, wherein at least one of the firstpolymer and the second polymer comprises a vinyl polymer comprisingrecurring units derived at least from glycidyl (meth)acrylate.

3. The composition of embodiment 1 or 2, wherein each of the firstpolymer latex and the second polymer latex comprises a vinyl polymerindependently comprising at least 75 weight % and up to and including 90weight % of recurring units derived from glycidyl (meth)acrylate, basedon the total weight of the vinyl polymer.

4. The composition of embodiment 3, wherein at least one of the firstpolymer latex and the second polymer latex comprises a vinyl polymerfurther comprising recurring units derived from an alkyl (meth)acrylatehaving an ester alkyl group having at least 2 carbon atoms.

5. The composition of embodiment 4, wherein at least one of the firstpolymer and the second polymer is crosslinked.

6. The composition of any of embodiments 1 to 5, wherein the firstpolymer and the second polymer independently have glass transitiontemperatures of at least 25° C.

7. The composition of any of embodiments 1 to 6, wherein the weightratio of the first polymer latex to the second polymer latex in a driedprimer layer formed therefrom is from 1:3 and to and including 3:1.

8. The composition of any of embodiments 1 to 7, wherein the firstsurfactant is an alkyl sulfonate sodium salt wherein the alkyl group hasat least 10 carbon atoms, and the second surfactant is an alkyl phenolsulfate ammonium salt having at least 3 ethylene oxide units.

9. The composition of any of embodiments 1 to 8, wherein the firstsurfactant is a sodium α-olefin (C₁₄-C₁₆) sulfonate, and the secondsurfactant is an ammonium salt of a sulfated polyethoxy nonylphenol.

10. The composition of any of embodiments 1 to 9, wherein the firstsurfactant is a compound represented by R—CH₂—CH—CH—CH₂—S(═O)₂O⁻Na⁺wherein R is a C₁₀, C₁₁, or C₁₂ hydrocarbon group, or mixtures of suchcompounds with different R groups that are any of C₁₀ to C₁₂hydrocarbons groups; and the second surfactant is represented byR′-phenyl-(O—CH₂CH₂)_(n)—S(═O)O₂ ⁻NH₄ ⁺ wherein R′ is a C₈ to C₁₂hydrocarbon group, and n is 3 to 10.

11. The composition of any of embodiments 1 to 10, wherein the firstsurfactant is present in a dried primer layer formed therefrom in anamount of at least 1 weight % and up to and including 3 weight %, andthe second surfactant is present in the dried primer layer in an amountof at least 0.35 weight % and up to and including 1.1 weight %, bothbased on the total dried primer layer weight.

12. The composition of any of embodiments 1 to 11, wherein the totalamount of the first and second surfactants in a dried primer layerformed therefrom is up to and including 3.35 weight %, based on thetotal dried primer layer weight.

13. A substrate comprising a support and a dried primer layer disposedon at least one supporting surface of the support, the dried primerlayer formed from the composition of any of embodiments 1 to 12comprising a mixture of the first and second polymer latexes describedabove.

14. The substrate of embodiment 13 that has an integrated transmittanceof at least 88%.

15. The substrate of embodiment 13 or 14 comprising a transparentpolymeric support and having the dried primer layer disposed directlythereon.

16. The substrate of any of embodiments 13 to 15, wherein the driedprimer layer has an average thickness of at least 0.05 μm and up to andincluding 0.4 μm.

17. The substrate of any of embodiments 13 to 16, comprising apoly(ethylene terephthalate) or poly(ethylene naphthalate) support.

18. The substrate of any of embodiments 13 to 17 that is a transparentpolymeric substrate comprising a transparent polyester support and thedried primer layer disposed directly on at least one supporting surfaceof the transparent polyester support,

wherein:

(i) the transparent polymeric substrate has an integrated transmittanceof at least 88%;

(ii) the dried primer layer has an average thickness of at least 0.05 μmand up to and including 0.2 μm, and comprises a mixture of:

-   -   a first polymer latex comprising a first polymer and a first        surfactant, wherein the first polymer comprises at least 75        weight % and up to and including 90 weight % of recurring units        derived from glycidyl (meth)acrylate and at least 10 weight %        and up to and including 25 weight % of recurring units derived        from n-butyl (meth)acrylate, based on the total first polymer        weight, which first polymer has a glass transition temperature        of at least 25° C. and up to and including 75° C., and the first        surfactant is a sodium α-olefin (C₁₄-C₁₆) sulfonate;    -   a second polymer latex comprising a second polymer and a second        surfactant that is different from the first surfactant, wherein        the second polymer comprises at least 75 weight % and up to and        including 90 weight % of recurring units derived from glycidyl        (meth)acrylate and at least 10 weight % and up to and including        25 weight % of recurring units derived from n-butyl        (meth)acrylate, based on the total second polymer weight, which        second polymer has a glass transition temperature of at least        25° C. and up to and including 75° C., and the second surfactant        is an ammonium salt of a sulfated polyethoxy nonylphenol;

(iii) the dried primer layer has a surface polarity of at least 28% andup to and including 50%;

(iv) the weight ratio of the first polymer latex to the second polymerlatex in the dried primer layer is from 1:1 and to and including 2.5:1;

(v) the first surfactant is present in the dried primer layer in anamount of at least 1 weight % and up to and including 3 weight %, basedon total dried primer weight;

(vi) the second surfactant is present in the dried primer layer in anamount of at least 0.35 weight % and up to and including 1.1 weight %,based on the total dried primer layer, and

(vii) the total amount of the first and second surfactants in the driedprimer layer is less than 3.35 weight %, based on the total dried primerlayer weight.

19. An article comprising a substrate of any of embodiments 13 to 18comprising a patterned material comprising lines having an average linewidth of less than 15 μm, which patterned material is disposed directlyon the dried primer layer.

20. The article of embodiment 20 that has an integrated transmittance ofat least 88%.

21. The article of embodiment 19 or 20 comprising a transparentpolymeric support and the dried primer layer disposed directly thereon.

22. The article of any of embodiments 19 to 21, wherein the patternedmaterial comprises an electrically-conductive metal or precursor thereofselected from the group consisting of gold, silver, copper, palladium,platinum, nickel, and precursors thereof.

23. The article of any of embodiments 19 to 22, wherein the patternedmaterial comprises a free radical curable composition, an acid catalyzedcurable composition, or a mixture of both a free radical curablecomposition and an acid catalyzed curable composition.

24. The article of any of embodiments 19 to 23, wherein the patternedmaterial comprises metal particles dispersed within a photocured orthermally cured composition.

25. The article of any of embodiments 19 to 24, wherein the patternedmaterial comprises particles of gold, silver, copper, palladium, orplatinum dispersed within a photocured or thermally cured compositionderived from both a free radical curable composition and an acidcatalyzed curable composition.

26. A method for providing a primed article with a patterned material ofany of embodiments 19 to 25, the method comprising:

providing a transparent polymeric substrate of any of embodiments 13 to18, and

providing a pattern of a patterned material directly onto the driedprimer layer.

27. The method of embodiment 1, wherein at least a portion of thepattern of patterned material comprises lines having an average linewidth of less than 15 μm.

28. The method of embodiment 26 or 27, wherein the at least a portion ofthe pattern of patterned material is present in a touch screen region ofthe primed article.

29. The method of any of embodiments 26 to 28, comprising:

providing the patterned material directly on the dried primer layer bydirect contact of the dried primer layer with a relief printing membercarrying the patterned material.

30. The method of any of embodiments 26 to 29, wherein the patternedmaterial comprises an electrically-conductive metal or precursorthereof.

31. The method of any of embodiments 26 to 30, wherein the patternedmaterial comprises is a photocurable or thermally curable compositionand metal particles.

32. The method of embodiment 31, further comprising:

curing the photocurable or thermally curable composition in thepatterned material.

33. The method of any of embodiments 26 to 32, wherein the patternedmaterial comprises a metal particles and the method further comprises:

electrolessly metal plating the pattern of patterned material.

34. A method for providing an electrically-conductive pattern on atransparent polymeric substrate, the method comprising:

providing a transparent polymeric substrate as described in any ofembodiments 13 to 18,

providing a pattern of a precursor electrically-conductive materialdirectly onto the dried primer layer, at least a portion of the patternof precursor electrically-conductive material comprising lines having anaverage line width of less than 15 μm,

converting the at least a portion of the pattern of precursorelectrically-conductive material to a pattern of electrically-conductivematerial that comprises electrically-conductive lines having an averageline width of less than 15 μm.

35. The method of embodiment 34, comprising:

providing the transparent polymeric substrate as a continuous web,

providing one or more individual patterns of a photocurable or thermallycurable composition as the precursor electrically-conductive materialdirectly on the dried primer layer in one or more individual portions ofthe continuous web, respectively, which photocurable or thermallycurable composition comprises metal seed particles,

converting each of the one or more individual patterns of photocurableor thermally curable composition by curing to form one or moreindividual cured patterns in the one or more individual portions, eachof the one or more individual cured patterns comprising the metal seedparticles, and

electrolessly plating the metal seed particles in each of the one ormore individual cured patterns to provide one or more individualelectrically-conductive patterns.

36. The method of embodiment 34 or 35, wherein each of the one or moreindividual electrically-conductive patterns comprises a touch regioncomprising electrically-conductive lines having an average line width ofless than 15 μm.

37. A product article obtained from the method of any of embodiments 34to 36, wherein the product article comprises at least one pattern of anelectrically-conductive material wherein at least a portion of thepattern of electrically-conductive material compriseselectrically-conductive lines having an average line width of less than15 μm, which portion of the pattern of electrically-conductive materialis disposed directly on the dried primer layer of the transparentpolymeric substrate.

38. A device comprising a transparent film that comprises:

one or more electrically-conductive metal patterns disposed directly ona transparent polymeric substrate of any of embodiments 13 to 18,

wherein each of the one or more electrically-conductive metal patternscomprises a touch region comprising electrically-conductive lines havingan average line width of less than 15 μm.

39. The device of embodiment 1, wherein the transparent film has anintegrated transmittance of at least 88%, and comprises the dried primerlayer disposed directly on the transparent polymer support that is atransparent polyester support.

40. A method for providing a plurality of precursor articles, the methodcomprising:

providing a continuous web of a transparent polymeric substrate havingthe properties of any of embodiments 13 to 18,

forming a first curable pattern directly on the dried primer layer in afirst portion of the continuous web, the first curable patterncomprising a photocurable or thermally curable composition comprisingseed metal particles, by direct contact of the dried primer layer in thefirst portion of the continuous web with a flexographic printing membercarrying the photocurable or thermally composition,

advancing the continuous web comprising the first portion comprising thefirst curable pattern to be proximate a curing station and curing thefirst curable pattern, thereby forming a first cured pattern on thefirst portion, which first cured pattern comprises the seed metalparticles,

forming a second curable pattern directly on the dried primer layer in asecond portion of the continuous web, the second curable patterncomprising the same or different photocurable or thermally curablecomposition comprising the same or different seed metal particles, bydirect contact with a flexographic printing member carrying the same ordifferent photocurable or thermally curable composition,

advancing the continuous web comprising the second portion comprisingthe second curable pattern to be proximate a curing station and curingthe second curable pattern, thereby forming a second cured pattern onthe second portion, which second cured pattern comprises the same ordifferent seed metal particles,

optionally, carrying out the forming and advancing features one or moretimes for additional respective portions of the continuous web using thesame or different curable or thermally curable composition and the sameor different flexographic printing member to form additional curedpatterns on the additional respective portions, and

winding up the continuous web comprising first, second, and optionaladditional cured patterns to form a roll of a plurality of precursorarticles.

41. The method of embodiment 40, wherein the same seed metal particlesare present in each of the multiple cured patterns, which seed metalparticles are gold particles, silver particles, copper particles,palladium particles, or platinum particles.

42. The method of embodiment 40 or 41, wherein the same photocurable orthermally curable composition is used in each forming feature for eachcurable pattern.

43. The method of any of embodiments 40 to 42, wherein the samephotocurable composition is used in each forming feature for eachcurable pattern, which photocurable composition comprises a free radicalcurable composition, an acid catalyzed curable composition, or both afree radical curable composition and an acid catalyzed curablecomposition.

44. The method of any of embodiments 40 to 43, wherein the continuousweb has an integrated transmittance of at least 88%, and comprises thedried primer layer disposed directly on the transparent polymer supportthat is a transparent polyester support.

The following Examples are provided to illustrate the practice of thisinvention and are not meant to be limiting in any manner.

Example 1: Preparation of Composition-Mixture of Polymer Latexes

Preparation of First Polymer Latex (Latex A):

Poly(glycidyl methacrylate-co-butyl acrylate) was synthesized by adding652 g of demineralized water to a 2 liter glass reactor. Another 651 gof demineralized water was added to a 2 liter glass head tank. Theagitators on both vessels were set at 150 RPM. A nitrogen atmosphere wasestablished in the system, and 30.9 g of Rhodacal® A246L anionicsurfactant (“first surfactant”) were added to each vessel. The reactorcontents temperature was raised to 60° C., and 526 g of glycidylmethacrylate and 92.3 g of n-butyl acrylate were added to the head tank.When the monomer emulsion had been prepared in the head tank and thetemperature was at 60° C., 6.16 g of azobis(4-cyano)valeric acid (75%)were added to the reactor. The contents of the head tank were meteredinto the reactor over 240 minutes and the reactor contents were stirredfor two hours at 60° C., followed by addition of 0.48 g of erythorbicacid dissolved in 9 g of water. Then, 1.35 g of 30 weight % hydrogenperoxide dissolved in 47 g of water, were added to the reactor in adropwise manner. The reactor contents were then stirred for anadditional hour at 60° C. The resulting first polymer latex was thencooled to 25° C. and filtered through a 30 μm cloth. This preparationyielded 1900 g of filtered first polymer latex at 32% solids. The firstpolymer median particle size was determined by UPA to be 53.1 nm.

Preparation of Second Polymer Latex (Latex B):

Poly(glycidyl methacrylate-co-butyl acrylate) was synthesized by adding675.2 g of demineralized water to a 2-liter glass reactor. To a 2 literglass head tank were added 674 g of demineralized water. The agitatorson both vessels were set at 150 RPM. A nitrogen atmosphere wasestablished in the system, and 7.72 g of Rhodapex® CO-436 anionicsurfactant (a “second surfactant”) were added to each vessel. Thereactor contents temperature was raised to 60° C., and 526 g of glycidylmethacrylate and 92.3 g of n-butyl acrylate were added to the head tank.When the monomer emulsion had been prepared in the head tank and thereactor contents temperature was at 60° C., 6.16 g ofazobis(4-cyano)valeric acid (75%) and 2.66 g of a 28% aqueous ammoniasolution were added to the reactor. The contents of the head tank weremetered into the reactor over 240 minutes and the reactor contents werestirred for two hours at 60° C., followed by addition of 0.48 g oferythorbic acid dissolved in 9 g of water. Then, 1.35 g of 30 weight %hydrogen peroxide dissolved in 47 g of water were added to the reactorin a dropwise fashion. The reactor contents were stirred for anadditional hour at 60° C. The resulting first polymer latex was thencooled to 25° C. and filtered through a 30 μm cloth. This preparationyielded 1900 g of filtered first polymer latex at 30.6% solids. Thefirst polymer median particle size was determined by UPA to be 87.1 nm.

The glass transition temperatures of various polymers obtained usingemulsion polymerization as described above and different monomer weightratios were obtained as follows:

Weight Ratio of Glycidyl T_(g) (as measured using Methacrylate ton-Butyl Acrylate DSC) 100:0  70° C. 85:15 43° C. 75:25 28° C.

Example 2: Preparation of Substrates and Articles

Primed poly(ethylene terephthalate) substrates were prepared in thefollowing manner.

Samples of transparent poly(ethylene terephthalate) (PET) film (orsupport) was were formed by extrusion and casting to a thicknessappropriate to yield a biaxially oriented film of 125 μm thickness afterstretching in both the machine and transverse directions. Prior to thestretching operation, a primer composition was applied and dried toprovide a dried primer layer on both opposing supportive sides of thePET support. The primer compositions tested contained either or both ofLatex A and Latex B described above. The resulting primed substratescomprising transparent supports and dried primer layers were thenstretched as noted to reduce shrinkage and haze. The various resultingprimed substrates A through N and average dry thickness of the resultingdried primer layers are described below in TABLE II.

The primed substrate identified as Sample B described in TABLE II wasprepared at a concentration of 20% total latex polymer using firstpolymer latex (Latex A) and second polymer latex (Latex B) in equalamounts, 0.2 weight % of Saponin in a 50 weight % solution, and 0.033weight % of Aerodisp® W7512S fumed silica particles (average size of 0.1spu). The primed substrates identified as Samples A, C, and D through Nwere prepared in a similar fashion with the amounts of the first polymerlatex and second polymer latex varied as noted in TABLE II. The primedsubstrate identified as Sample D also contained 1 weight % ofresorcinol. The primed substrate identified as Sample N was prepared inthe same manner as the primer composition identified as Sample A exceptthat Rhodacal® A246L anionic surfactant (“first surfactant”) was addedto the dispersion in an amount of 2 weight % relative to the totalsecond polymer weight in Latex B (thus, both a first surfactant and asecond surfactant were incorporated but the first surfactant was notincorporated as part of a distinct polymer latex).

Example 3

The mixtures of first and second polymer latexes described above andvarious primed substrates were used to provide printed patterns ofpatterned material including electrically-conductive patterns in thefollowing manner.

% Surface Polarity:

Based on the known Fowkes energy method, percent surface polarity of agiven dry surface (for example, a dried primer layer or a dried layer ofa polymer latex) was determined by first measuring the 2 minute contactangle (θ) of each of a drop of water and a drop of diiodomethane on thegiven dry surface. Knowing the dispersive (γ^(d) _(L)) and polar (γ^(p)_(L)) components of the liquid surface tension (γ_(L)) for each of thefluids (see TABLE I below) the polar and dispersive components of thegiven dry surface were calculated using Equation 1 shown below. Thepercent surface polarity was then calculated using Equation 2 shownbelow and in the TABLE I.

TABLE I Fluid γ^(d)L γ^(p)L γL = γ^(d)L + γ^(p)L Water 21.8 51.0 72.8Diiodomethane 48.5 2.3 50.8γ_(L)(1+cos θ)=2[(γ^(d) _(L)γ^(p) _(L))^(1/2)+(γ^(d) _(S)γ^(p)_(S))^(1/2)]  Equation 1% surface polarity=100[γ^(p) _(S)/(γ^(d) _(S)+γ^(p) _(S))]  Equation 2Photocurable Compositions (“Inks”)

Photocurable Composition 1 (Ink 1):

This photocurable composition (or patterned material) is similar to thatdescribed in Invention Example 1 of U.S. Ser. No. 14/174,879 (notedabove) and in Invention Example 1 of U.S. Ser. No. 14/197,293 (alsonoted above), and comprised at least the following components formedinto a 100 g aliquot:

14.4 g of epoxy acrylates (CN 153 from Sartomer), 9.9 g of poly(ethyleneglycol) diacrylate (M_(n) of 258, Sigma-Aldrich), 2.1 g of poly(ethyleneglycol) diacrylate (M_(n) of 575, Sigma-Aldrich), 10.8 g ofpentaerythritol tetraacrylate (Sigma-Aldrich), 0.8 g of triarylsulfonium salt hexafluorophosphate mixed in 50% propylene carbonate(Sigma-Aldrich), 0.8 g of triaryl sulfonium salt hexafluoroantimonatemixed in 50% propylene carbonate (Sigma-Aldrich), 2.4 g of free radicalphotoinitiator hydroxycyclohexyl phenyl ketone (Sigma-Aldrich), 1.2 g offree radical photoinitiatormethyl-4′-(methylthio)-2-morpholinopropiophenone (Sigma-Aldrich), 19.5 gof silver nanoparticles (Novacentrix, 20-25 nm average particle size,Ag-25-ST3), 1.1 g of carbon nanoparticles (US1074 from US Nano), 0.001 gof 9-fluorenone (Sigma-Aldrich), and 35 g of 1-methoxy isopropanol(Sigma-Aldrich) solvent.

Photocurable Composition 2 (Ink 2):

This photocurable composition (or patterned material) was preparedsimilarly to Ink 1, but did not contain 9-fluorenone.

Printing the Photocurable Composition:

Samples of printed patterns of the photocurable composition describedabove on various primed PET substrates were obtained using a benchtoptest printer, “IGT F1 Printability Tester” from IGT Testing SystemsInc., Arlington Heights, Ill., in the flexographic mode. The Aniloxroller system that was used to apply the photocurable composition toflexographic printing plates had values of 1.3 BCMI and 1803 lpi, asspecified by IGT. The printed patterns were made at ambient temperatureusing an Anilox force of 20N, a print force of 10N, and a print speed of0.20 m/s.

The flexographic plates used for printing the photocurable compositionwere samples of the commercially available Kodak Flexcel NX photopolymerplate precursors (Eastman Kodak Company) that had been imaged using amask that had a predetermined pattern written using the Kodak SquareSpot laser technology at a resolution of 12,800 dpi. The exposedflexographic plate precursors were UV exposed and processed (developed)using known conditions suggested for these relief printing members bythe manufacturer. The resulting flexographic printing plates were each1.14 mm thick (including the PET). The backing tape used to mount theflexographic plate to the printing form cylinder was the 1120 Beige tapefrom 3M Company, which was 20 mil (0.051 cm) thick with had a Shore A of55. The relief image design in the flexographic printing plates includeda grid pattern with fine lines that had a width at the top reliefsurface of 7 μm. The printed average line widths on the primed PETsubstrates shown below were obtained from the patterns printed with thenoted grid pattern.

After printing, each printed pattern of photocurable composition wasirradiated with UV radiation using a Fusion 300 WPI medium pressuremercury lamp providing irradiation wavelengths between 190-1500 nm, withan approximate exposure of 298 mJ/cm² to cure each printed pattern ofpatterned material. The printed average line widths of the curedpatterns were measured in both transmission and reflection mode using anOlympus BH-2 optical microscope.

Electroless Metal Plating:

Intermediate articles comprising the cured patterns on the variousprimed substrates were electrolessly copper plated by immersing theintermediate articles with the cured patterns m for 7 minutes at 45° C.in a beaker containing Enplate Cu-406 electroless plating solution(Enthone), followed by rinsing with distilled water and drying withnitrogen, to form product articles with electrically-conductive patternsdisposed on the primed substrates.

Adhesion Testing (“Tape Removal Test”:

Immediately after electroless plating, a piece of Scotch® 810 Magic Tapeadhesive tape from 3M Corporation was applied to an electrolessly platedpattern in each product article and then pulled off the surface of theproduct article. The amount of copper removed by this operation wasrecorded as an indication of adhesion of the electrolessly platedpattern to the primed PET substrate. The results are shown below inTABLE II.

The coating appearance of each substrate was assessed on a scale of 0 to5 ratings wherein a “0” rating indicates no visible differences insurface uniformity, a “1” rating indicates barely noticeable surfacenon-uniformities, a “2” rating indicates minor but noticeable surfacenon-uniformities, a “3” rating indicates clearly noticeable surfacenon-uniformities, a “4” rating indicates significant surfacenon-uniformities including high haze and iridescence, and a “5” ratingindicates severe surface non-uniformities including high haze andiridescence.

Also in TABLE II below, haze (%) and “% T” were measured using aHazegard Plus haze meter (BYK Gardner) wherein “haze” is a measure oflight scatter through the substrate and higher numbers affecting itsclarity; and “% T” is the measure of integrated transmittance throughthe substrate with higher numbers indicating higher transparency.

Colorimetry values of each substrate was measured using an Ultrascan XEcolorimeter (Hunter) and the results are reported in standard CIELABnomenclature wherein b* in TABLE II represents the color of thesubstrate on the blue-yellow axis and more positive b* values indicate amore yellow appearance in the substrate.

In TABLE II, “YI” represents a yellowness index (E313 standard), whichis a calculated value that incorporates CIELAB measurements such thatincreasing YI values indicate a more yellow appearance in the substrate.

The grid line evaluations were carried out on both supporting sides ofthe substrate. The line width results were observed to be essentiallythe same for both supporting sides.

In TABLE II, “Ink” refers to either Ink 1 or Ink 2 as identified above.

TABLE II Total Surface Grid Average Energy % line Tape Thickness (dyne/Surface Coating width removal Sample Latex A Latex B (μm) cm) PolarityHaze % T b* YI Appearance Ink (μm) Test A 0 100 0.11 50 26 1.22 93.322.31 4.28 4 2 11 None Comparison B 50 50 0.11 51 38 0.57 94.06 1.93 3.494 2 7 Small Invention amount Cu only C 100 0 0.11 59 62 0.46 93.39 2.424.49 3 2 No complete Comparison lines/ removal dewet D* 100 0 0.11 54 550.45 93.58 2.25 4.14 4 2 Lines None Comparison broken up E 25 75 0.09246 19 0.76 94.38 1.41 2.46 2 1 7.4 None Invention F 50 50 0.092 52 350.49 94.52 1 1.68 2 1 6.7 None Invention G 75 25 0.092 48 42 0.54 94.511.25 2.15 2 1 5.2 None Invention H* 50 50 0.092 46 24 0.66 94.28 1 1.725 1 5.5 None Invention I 50 50 0.083 51 33 0.59 94.4 0.32 0.41 2 1 6.3None Invention J 50 50 0.092 49 39 0.57 94.5 1 1.69 1 8.5 None InventionK 50 50 0.092 49 39 0.67 94.14 1.48 2.62 1 7.7 None Invention L 60 400.092 47 38 0.46 94.55 0.84 1.38 1 8 None Invention M 70 30 0.092 51 440.55 94.49 0.64 1 1 8.4 None Invention N** 0 100 0.092 46 34 0.59 94.41.3 2.26 5 1 5.7 None; Comparison small piece of Cu in pad area *Coatingsolution contained resorcinol **First surfactant added to Latex Bseparately

The printed articles identified as Comparison Examples A, C, and Dexhibited similar total surface energy, but different % surfacepolarity, resulting in differences in printing of the patternedmaterial. Comparison Example A yielded printed electrically-conductivelines having an average line width greater than the average line widthsobtained using printed articles identified as Invention Examples B and Ethrough M. The printed articles identified as Comparison Examples C andD exhibited poor printed line quality.

The printed articles identified as Invention Examples B and E through Mprepared using a dried primer layer according to the present invention(mixture of first and second polymer latexes) to provide % surfacepolarity of between 19 and 44, produced electrically-conductive lineshaving an average line width of less than 10 μm and of good quality anddemonstrated good electroless plating performance and adhesion of theelectrolessly plated copper to the primed substrate. The printedarticles identified as Invention Examples E-G and I-L exhibitedparticularly good coating appearance, low haze, and low color.

The printed article identified as Comparison Example N demonstrated thatmere addition of an additional surfactant (“first surfactant”) alone toa single polymer latex (“second” polymer latex, or Latex B) was notsufficient to provide the necessary coating uniformity. Rather,according to the present invention, the first and second surfactantsneed to be provided to the dried primer layer by way of the individualfirst and second polymer latexes.

The printed article identified as Invention Example H did not exhibitthe best coating appearance but had desirable electrically-conductiveline qualities.

Example 4

Precursor articles containing primed substrates were formed using aphotocurable composition similar to that described in Example 1 using aMark-Andy press at 20 ft/m (6.06 m/min) and process similar to thatdescribed in FIG. 1 to provide patterns of the photocurable compositionas narrow lines on both supporting sides of a PET support.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof; but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

PARTS LIST

-   100 flexographic printing system-   102 supply roll-   104 take-up roll-   105 roll-to-roll direction-   106 roller-   107 roller-   110 print module-   111 plate cylinder-   112 flexographic printing plate (or flexographic printing member)-   113 raised features-   114 impression cylinder-   115 Anilox roller-   116 UV curing station-   120 print module-   121 plate cylinder-   122 flexographic printing plate (or flexographic printing member)-   124 impression cylinder-   125 Anilox roller-   126 UV curing station-   130 print module-   131 plate cylinder-   132 flexographic printing plate (or flexographic printing member)-   134 impression cylinder-   135 Anilox roller-   136 UV curing station-   140 print module-   141 plate cylinder-   142 flexographic printing plate (or flexographic printing member)-   144 impression cylinder-   145 Anilox roller-   146 UV curing station-   150 substrate (or continuous web)-   151 first supporting side-   152 second (opposing) supporting side-   300 apparatus (or device)-   310 touch screen-   320 display device-   330 touch sensor-   340 transparent substrate-   341 first supporting side-   342 second supporting side-   350 electrically-conductive pattern-   351 fine lines-   352 grid-   353 fine lines-   354 channel pads-   355 grid column-   356 interconnect lines-   358 connector pads-   360 electrically-conductive pattern-   361 fine lines-   362 grid-   363 fine lines-   364 channel pads-   365 grid row-   366 interconnect lines-   368 connector pads-   380 controller

The invention claimed is:
 1. A device comprising a transparent film thatcomprises: one or more electrically-conductive metal patterns disposeddirectly on a transparent polymeric substrate that comprises atransparent polymer support and a dried primer layer disposed on atleast one supporting surface of the transparent polymer support, thedried primer layer comprising a mixture of: a first polymer latexcomprising a first polymer and a first surfactant such that a driedcoating of the first polymer latex has a surface polarity of at least50%, and a second polymer latex comprising a second polymer and a secondsurfactant that is different from the first surfactant such that a driedcoating of the second polymer latex has a surface polarity of less thanor equal to 27%, wherein the dried primer layer has a surface polarityof at least 15% and up to and including 50%, and wherein each of the oneor more electrically-conductive metal patterns comprises a touch regioncomprising electrically-conductive lines having an average line width ofless than 15 μm.
 2. The device of claim 1, wherein the transparent filmhas an integrated transmittance of at least 88%, and comprises the driedprimer layer disposed directly on the transparent polymer support thatis a transparent polyester support.
 3. The device of claim 1, wherein atleast one of the first polymer and the second polymer comprises a vinylpolymer comprising recurring units derived at least from glycidyl(meth)acrylate.
 4. The device of claim 1, wherein each of the firstpolymer latex and the second polymer latex comprises a vinyl polymerindependently comprising at least 75 weight % and up to and including 90weight % of recurring units derived from glycidyl (meth)acrylate, basedon the total weight of the vinyl polymer.
 5. The device of claim 4,wherein at least one of the first polymer latex and the second polymerlatex comprises a vinyl polymer further comprising recurring unitsderived from an alkyl (meth)acrylate having an ester alkyl group havingat least 2 carbon atoms.
 6. The device of claim 1, wherein the weightratio of the first polymer latex to the second polymer latex in thedried primer layer is from 1:3 and to and including 3:1.
 7. The deviceof claim 1, wherein the first surfactant is an alkyl sulfonate sodiumsalt wherein the alkyl group has at least 10 carbon atoms, and thesecond surfactant is an alkyl phenol sulfate ammonium salt having atleast 3 ethylene oxide units.
 8. The device of claim 1, wherein thefirst surfactant is a sodium α-olefin (C₁₄-C₁₆) sulfonate, and thesecond surfactant is an ammonium salt of a sulfated polyethoxynonylphenol.
 9. The device of claim 1, wherein the first surfactant is acompound represented by R—CH₂—CH═CH—CH₂—S(O)₂O⁻Na⁺ wherein R is a C₁₀,C₁₁, or C₁₂ hydrocarbon group, or mixtures of such compounds withdifferent R groups that are any of C₁₀ to C₁₂ hydrocarbons groups; andthe second surfactant is represented byR′-phenyl-(O—CH₂CH₂CH₂)_(n)—S(═O)O₂ ⁻NH₄ ⁺ wherein R′ is a C₈ to C₁₂hydrocarbon group, and n is 3 to
 10. 10. The device of claim 1, whereinthe first surfactant is present in the dried primer layer in an amountof at least 1 weight % and up to and including 3 weight %, the secondsurfactant is present in the dried primer layer in an amount of at least0.35 weight % and up to and including 1.1 weight %, both based on thetotal dried primer layer weight, and the total amount of the first andsecond surfactants in the dried primer layer is up to and including 3.35weight %, based on the total dried primer layer weight.